Co-reporter:Zhiliang Liu, Xinghua Chang, Teng Wang, Wei Li, Haidong Ju, Xinyao Zheng, Xiuqi Wu, Cong Wang, Jie Zheng, and Xingguo Li
ACS Nano June 27, 2017 Volume 11(Issue 6) pp:6065-6065
Publication Date(Web):June 1, 2017
DOI:10.1021/acsnano.7b02021
Silica can be converted to silicon by magnesium reduction. Here, this classical reaction is renovated for more efficient preparation of silicon nanoparticles (nano-Si). By reducing the particle size of the starting materials, the reaction can be completed within 10 min by mechanical milling at ambient temperature. The obtained nano-Si with high surface reactivity are directly reacted with 1-pentanol to form an alkoxyl-functionalized hydrophobic colloid, which significantly simplifies the separation process and minimizes the loss of small Si particles. Nano-Si in 5 g scale can be obtained in one single batch with laboratory scale setups with very high yield of 89%. Utilizing the excellent dispersion in ethanol of the alkoxyl-functionalized nano-Si, surface carbon coating can be readily achieved by using ethanol soluble oligomeric phenolic resin as the precursor. The nano-Si after carbon coating exhibit excellent lithium storage performance comparable to the state of the art Si-based anode materials, featured for the high reversible capacity of 1756 mAh·g–1 after 500 cycles at a current density of 2.1 A·g–1. The preparation approach will effectively promote the development of nano-Si-based anode materials for lithium-ion batteries.Keywords: colloidal; lithium-ion batteries; magnesium; silicon nanoparticles; surface functionalization;
Co-reporter:Huaiwei Zhang, Xinyao Zheng, Xiao Tian, Yang Liu, Xingguo Li
Progress in Natural Science: Materials International 2017 Volume 27, Issue 1(Volume 27, Issue 1) pp:
Publication Date(Web):1 February 2017
DOI:10.1016/j.pnsc.2016.12.011
As the most possibility applied to the next generation negative electrode materials of Ni/ MH second battery, rare earth (RE)-magnesium (Mg) based alloys have been developed over the last few years. Recent advances about the RE-Mg based intermetallic compounds on the crystal structures, hydrogenation behaviors and electrochemical performances are reviewed in the paper. On the other hand, new results about the preparation and modification methods of the alloys are also covered in details.
Co-reporter:Xinghua Chang, Zewei Xie, Zhiliang Liu, Xinyao Zheng, Jie Zheng, Xingguo Li
Nano Energy 2017 Volume 41(Volume 41) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.nanoen.2017.10.017
•Positive side of the surface alumina: enabling self-assembly of Al nanoparticles and GO into a 3D composite structure.•Negative side of the surface alumina: blocking Li+ transport.•The oxide layer can be removed by thermal etching using anhydrous HCl to vitalize the lithium storage capability of Al.•High lithium storage performance (1041 mAh g−1 after 500 cycles) is achieved for the 3D Al/rGO composite.Aluminum is an attractive anode material for lithium ion batteries due to its low cost, high capacity and low equilibrium potential for lithiation/delithiation. The compact surface oxide layer is usually considered to be detrimental for lithium storage in Al due to its poor conductivity for Li+. Here we show that the Al oxide layer, which is positively charged, can be utilized to assist the homogeneous loading of the Al nanoparticles on to the negatively charged graphene oxide (GO) sheets. During the thermal reduction of GO to reduced GO (rGO), anhydrous HCl is introduced to selectively remove the surface oxide on the Al particles. The vitalized Al/rGO composite exhibits high lithium storage capacity of 1041 mAh g−1 after 500 cycles at current density of 500 mA g−1. The results demonstrate how the double edged surface oxide layer on Al nanoparticles can be manipulated to enable high performance lithium storage in Al, which is illuminating for the application of Al as a high performance, low cost anode material for lithium ion batteries.Download high-res image (191KB)Download full-size image
Co-reporter:Kai Fu, Guoling Li, Jigang Li, Yang Liu, Wenhuai Tian, Xingguo Li
Journal of Alloys and Compounds 2017 Volume 696(Volume 696) pp:
Publication Date(Web):5 March 2017
DOI:10.1016/j.jallcom.2016.11.182
•PCI measurements with high accuracy has been carried out.•A first assessment of Dy-H system has been carried out by the CALPHAD method.•A set of self-consistent thermodynamic parameters was derived for this system.The dysprosium-hydrogen (Dy-H) binary system in the full range of H/Dy = 0 to 3.0 is investigated by accurate pressure composition isotherm (PCI) measurement, including a PCI measurement of the β-DyH2/γ-DyH3 transition for the first time. The Dy/β-DyH2 biphasic region shows well defined plateaus in the range of H/Dy = 0.41 to 1.65 at 650 °C and gradually shrinks to 0.54 to 1.23 at 900 °C, with transition enthalpy of 213.1 ± 2.8 kJ/mol H2. The β-DyH2/γ-DyH3 biphasic region also shows well defined plateaus from 250 °C to 325 °C, but with much narrower composition region of H/Dy from 2.3 to 2.9. The transition enthalpy is 79.3 ± 2.2 kJ/mol H2. The phase diagram and thermodynamic parameters are calculated with the CALPHAD method using the measured PCI data. The obtained results are in very good agreement with our experimental data and the published data reported in literature. The results provide more comprehensive and quantitative insights into the key thermodynamic properties of the Dy-H system.
Co-reporter:Jun Chen;Jun Fu;Kai Fu;Rui Xiao;Yong Wu;Xinyao Zheng;Zhiliang Liu;Jie Zheng
Journal of Materials Chemistry A 2017 vol. 5(Issue 27) pp:14310-14318
Publication Date(Web):2017/07/11
DOI:10.1039/C7TA01954H
The hydrogen evolution reaction (HER) during the electrochemical oxidation of borohydride is the major efficiency loss in direct borohydride fuel cells (DBFCs). Here we show that an YH2–Pd thin film electrode, which combines catalysis on the Pd layer and H storage in the YH2 layer, can effectively promote the energy utilization efficiency. The YH2 layer can absorb the atomic H generated during the BH4− oxidation on the Pd layer and effectively suppress HER. The absorbed H can be further oxidized into H2O in NaOH solution, allowing full utilization of the 8 electrons in BH4− oxidation. The YH2–Pd electrode can be regarded as a hybridization of the anodes in conventional DBFCs and nickel-metal hydride batteries. The hydrogen absorption/desorption during the electrochemical process is in situ monitored by optical transmittance measurements, which provide key insights into the interconversion mechanisms and energetics of the hydridic, neutral and protonic hydrogen species.
Co-reporter:Yong Wu;Xiaojing Jiang;Jun Chen;Yue Qi;Yuxuan Zhang;He Fu;Jie Zheng
Dalton Transactions 2017 vol. 46(Issue 14) pp:4499-4503
Publication Date(Web):2017/04/05
DOI:10.1039/C7DT00337D
Boric acid effectively promotes the dehydrogenation of lithium borohydride due to the interactions between protonic and hydridic hydrogen. The simple mixture of LiBH4–(4/3)B(OH)3 can release 5.6 wt% hydrogen below 180 °C with only a trace amount of water, thus constituting a highly attractive single-use hydrogen storage material.
Co-reporter:Zhiliang Liu;Xinghua Chang;Bingxue Sun;Sungjin Yang;Jie Zheng
Chemical Communications 2017 vol. 53(Issue 46) pp:6223-6226
Publication Date(Web):2017/06/06
DOI:10.1039/C7CC02857A
SiCl4 can be directly reduced to nano-Si with commercial Na metal under solvent-free conditions by mechanical milling. Crystalline nano-Si with an average size of 25 nm and quite uniform size distribution can be obtained, which shows excellent lithium storage performance, for a high reversible capacity of 1600 mA h g−1 after 500 cycles at 2.1 A g−1.
Co-reporter:Huaiwei Zhang, Xinyao Zheng, Teng Wang, Xingguo Li
Materials & Design 2017 Volume 114(Volume 114) pp:
Publication Date(Web):15 January 2017
DOI:10.1016/j.matdes.2016.11.102
•The cycle stability was effectively promoted with the surface coating process.•The film as the catalyst improves the electrochemical performances of the system.•The hydrides intermediate mechanism was firstly proposed.The electrochemical properties of hydrogen storage alloys were significantly improved through coating a molybdenum nano-film. The encapsulated electrodes with a Mo nano film have the superior cycle life than the original, the coated electrode exhibits a much better anticorrosion ability and the higher electrochemical activity. In addition, the reactions and mechanisms of discharge process were also investigated.Download high-res image (159KB)Download full-size image
Co-reporter:Xiaojuan Wang, Leran Zou, He Fu, Yifu Xiong, Zixu Tao, Jie Zheng, and Xingguo Li
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 13) pp:8436
Publication Date(Web):March 3, 2016
DOI:10.1021/acsami.5b12102
A highly efficient noble-metal-free catalyst for the oxygen reduction reaction (ORR) is derived from a composite of polyaniline (PANI) and Prussian blue analogue (PBA, Co3[Fe(CN)6]2) by pyrolysis. The composite consists of 2–5 nm PBA nanocrystals homogeneously dispersed in PANI. During the pyrolysis, the PBA nanocrystals serve as both the template for the pore formation and the precursor for the ORR active sites, which results in a nanoporous structure strongly coupled with the ORR active sites. The catalyst exhibits superior ORR performance in both alkaline and acidic electrolyte, comparable to that of the commercial Pt/C with 20 wt % Pt loading.Keywords: electrocatalysts; oxygen reduction; polyaniline; porous carbon; Prussian blue
Co-reporter:Kai Fu, Guoling Li, Jigang Li, Yang Liu, Wenhuai Tian, Jie Zheng, Xingguo Li
Journal of Alloys and Compounds 2016 Volume 673() pp:131-137
Publication Date(Web):15 July 2016
DOI:10.1016/j.jallcom.2016.02.201
•PCI measurements with high accuracy has been carried out.•A first assessment of Gd–H system has been carried out by the CALPHAD method.•A set of self-consistent thermodynamic parameters was derived for this system.The thermodynamics of the gadolinium-hydrogen (Gd–H) binary system (H/Gd = 0.0–2.0) between 650 and 900 °C is studied by pressure composition isotherm measurement. Significant H dissolution in Gd is observed, up to H/Gd = 0.34 at 650 °C and 0.55 at 900 °C. The metal-rich phase boundary of nonstoichiometric gadolinium dihydride was found to occur with nominal composition of GdH1.80 at 650 °C and GdH1.53 at 900 °C. The results are in fairly good agreement with previous experimental work but with improved accuracy. The binary phase diagram is obtained using the CALPHAD method. The thermodynamic study here assists the understanding on the efficient deoxygenation effect by the H in Gd for Gd purification.
Co-reporter:Xiao Tian, Wei Wei, Ruxia Duan, Xinyao Zheng, Huaiwei Zhang, O. Tegus, Xingguo Li
Journal of Alloys and Compounds 2016 Volume 672() pp:104-109
Publication Date(Web):5 July 2016
DOI:10.1016/j.jallcom.2016.02.167
•La–Mg–Ni-based alloy was synthesized by melting, milling and subsequent annealing.•Mg atoms exist in the La2Ni7 phase prior to LaNi5 phase.•The La0.70MgxNi2.45Co0.75Al0.30 alloys consist of the LaNi5 and (La, Mg)2Ni7.•The more Mg element the alloys contain, the easier aggregation Mg atom is.•The Cmax of La0.70MgxNi2.45Co0.75Al0.30 alloy first increases and then decreases with rising x.The as-cast alloy with the composition of La0.70Ni2.45Co0.75Al0.30 was prepared by vacuum arc melting. La–Mg–Ni-based La0.70MgxNi2.45Co0.75Al0.30 hydrogen storage alloy has been synthesized by high-energy vibratory milling blending of the La0.70Ni2.45Co0.75Al0.30 as-cast alloy and elemental Mg, followed by an isothermal annealing. The microstructures and electrochemical properties of the La0.70Ni2.45Co0.75Al0.30 and La0.70MgxNi2.45Co0.75Al0.30 alloys were investigated by XRD, SEM and electrochemical measurements. The XRD analysis and Rietveld refinement showed that the as-cast La0.70Ni2.45Co0.75Al0.30 alloy consists of single LaNi5 phase, whereas the La0.70MgxNi2.45Co0.75Al0.30 alloys contain the LaNi5 and (La, Mg)2Ni7. The electrochemical measurements indicated that the maximum discharge capacity and discharge potential characteristic of the La0.70MgxNi2.45Co0.75Al0.30 alloys increases first and then decreases with increasing x. The maximum discharge capacity and discharge potential characteristic of alloy reaches the optimum when x is 0.36. The cyclic stability of the La0.70MgxNi2.45Co0.75Al0.30 alloy with a smaller quantity of Mg is better than that of the alloy with a larger quantity of Mg.
Co-reporter:Huaiyu Shao, Xingguo Li
Journal of Alloys and Compounds 2016 Volume 667() pp:191-197
Publication Date(Web):15 May 2016
DOI:10.1016/j.jallcom.2016.01.180
•Nanometer and micrometer Mg2Ni-based alloys were synthesized from metal particles.•The nano-Mg2Ni alloy shows best gaseous absorption capacity and kinetics.•The nano-Mg2Ni0.75Cu0.25 alloy shows best electrochemical performance.•Effect of nanostructure on gas absorption/electrochemical property was clarified.•Effect of partial substitution on these properties was also clarified.Mg2Ni-based alloys have been intensively investigated as gaseous hydrogen absorption materials and negative electrode materials for Nickel-Metal Hydride (Ni–MH) battery. In this work, three Mg2Ni-based samples (micrometer Mg2Ni, nanometer Mg2Ni and nanometer Mg2Ni0.75Cu0.25) were synthesized from Mg, Ni and Cu nanoparticles and commercially available micrometer Ni particles. The metal nanoparticles were fabricated by hydrogen plasma metal reaction technique. The structure and morphology of these three Mg2Ni-based samples were studied. Gaseous hydrogen absorption and electrochemical properties of these samples were investigated and compared. Amongst these three samples, the nanometer Mg2Ni shows best gas absorption kinetics of 3.0 wt.% in 1 min under 4 MPa hydrogen at 623 K; the nanometer Mg2Ni0.75Cu0.25 sample shows a highest first cycle electrochemical capacity of 346 mAh/g. The effect of nanostructure and partial substitution on gas absorption and electrochemical performance was clarified.
Co-reporter:Chongyun Wang, Wei Wang, Gongbiao Xin, Guoling Li, Jie Zheng, Wenhuai Tian, Xingguo Li
European Polymer Journal 2016 Volume 74() pp:43-50
Publication Date(Web):January 2016
DOI:10.1016/j.eurpolymj.2015.10.027
•The interactions can be changed by the surface functionalization of GO sheets.•The interactions play an importing role in mediating the phase change temperature.•The phase change behaviors can be mediated by surface modification.This paper carries out an extensive study on the phase change behavior of polyethylene glycol (PEG) on modified graphene oxide (GO). Distinct phase change behaviors are observed on GO, reduced GO (rGO) and carboxylic functionalized GO (GO-COOH) composites, which is attributed to the different surface functional groups on GO sheets. Notably, the introduction of supporting materials results in lower melting point of PEG, in the order of GO-COOH < GO < rGO at the same PEG content. The crystallization fraction of PEG follows the same trend. A significant depression in melting point of 16.8 °C is observed for the PEG/GO-COOH composite with 80 wt% PEG. The correlation between the phase change behaviors and the surface functional groups is discussed. The study suggests that the phase change behaviors in shape-stabilized phase change materials can be mediated by surface modification with different functional groups.The introduction of supporting materials results in lower melting point of PEG, in the order of GO-COOH < GO < rGO at the same PEG content. It could be concluded that the phase change behaviors in shape-stabilized phase change materials can be mediated by surface modification with different functional groups.
Co-reporter:Guoling Li, Heng Guo, Li Li, Chongyun Wang, Jie Zheng, Wenhuai Tian, Heping Li, Xingguo Li
Journal of Alloys and Compounds 2016 Volume 659() pp:1-7
Publication Date(Web):25 February 2016
DOI:10.1016/j.jallcom.2015.10.180
•The final purity of terbium can reach to 99.9521%.•The temperature distribution and the gas flow can be simulated.•Hydrogen H I spectra dissociate from H2 can be detected.•Impurities emitted by atoms, oxide and hydride molecules can be detected.•Activated hydrogen atoms bringing special physical and chemical interactions.The refining of terbium (Tb) by plasma arc melting using pure Ar and Ar + H2 mixture was examined, respectively. The temperature distribution and gas flow of the plasma arc during the melting process were simulated. The residual metallic impurities were examined by inductively coupled plasma-atomic emission spectrometer. Experimental results show that both methods of argon plasma arc melting (APAM) and hydrogen-argon plasma arc melting (HAPAM) can lead to a good removal of metallic impurities despite of high initial concentrations. HAPAM displays a better refining effect of Tb metal. Activated hydrogen atoms dissociated in high temperature plasma arc, bringing on special chemical interactions, are supposed to be the cause for the wonderful refining effect. The detailed behaviors of impurities and hydrogen atoms are discussed systematically in this study.
Co-reporter:Xiaojuan Wang, Xinxin Fan, Honghong Lin, He Fu, Teng Wang, Jie Zheng and Xingguo Li
RSC Advances 2016 vol. 6(Issue 44) pp:37965-37973
Publication Date(Web):04 Apr 2016
DOI:10.1039/C6RA04771H
In this work we report a highly efficient Co based catalyst for the oxygen reduction reaction (ORR) with highly dispersed Co sites on N-doped carbon. The catalyst is derived from a ZnCo bimetallic metal organic framework (MOF) by heat treatment in an inert atmosphere at 1000 °C. Zn is simultaneously eliminated during the pyrolysis due to its high volatility at high temperature, yielding a highly porous structure with homogeneous Co loading. Another effect of Zn is to disperse Co in the MOF precursor, which effectively inhibits the aggregation of Co after pyrolysis. The best ORR performance is achieved when 5% Zn is substituted by Co in the MOF precursor. The resulting catalyst shows a high half wave potential of 0.90 V vs. reversible hydrogen electrode in 0.1 M KOH solution, which is mainly attributed to the high dispersion of the ORR active Co sites.
Co-reporter:Jun Chen, Cong Wang, Yong Wu, He Fu, Jie Zheng and Xingguo Li
RSC Advances 2016 vol. 6(Issue 43) pp:36863-36869
Publication Date(Web):31 Mar 2016
DOI:10.1039/C6RA04410G
The reaction of water with hydrides (hydrolysis reaction) is very attractive for onsite hydrogen generation. Instead of using liquid water like in most cases, we demonstrate that hydrogen generation from hydrolysis reactions can also occur in the solid state. By simply heating mixtures of hydrated solids and hydrides, hydrogen generation is readily achieved through the recombination from the protonic hydrogen in the hydrated solids and the hydridic hydrogen in the hydride. The composites 5CaH2 + Na4P2O7·10H2O and NaBH4 + H2C2O4·2H2O give attainable gravimetric hydrogen storage capacity of 2.76% at 40 °C and 2.79% at 70 °C with rapid response, respectively. The dehydrogenation temperature can be controlled by the dehydration temperature of the hydrated solids. This innovative hydrogen generation approach provides a temperature activated, easy to control solution for onsite hydrogen generation.
Co-reporter:He Fu, Xiaojuan Wang, Yunqi Shao, Jun Chen, Xiu Zhang, Hui Fu, Jie Zheng, Xingguo Li
International Journal of Hydrogen Energy 2016 Volume 41(Issue 1) pp:384-391
Publication Date(Web):5 January 2016
DOI:10.1016/j.ijhydene.2015.10.081
•The etherate of LiB3H8 is synthesized via the reaction of Li/Hg and BH3·THF.•The dehydrogenation property of LiB3H8 is investigated.•The process of the synthetic reaction is monitored by NMR spectra.Octahydrotriborates are found to be key intermediates in the dehydrogenation of many borohydrides. In this work, LiB3H8‧1.5THF is synthesized via the reaction between lithium amalgam and BH3‧THF. The structure is confirmed by 11B NMR and FT-IR spectrometry. The synthetic reaction of LiB3H8‧1.5THF is monitored by using 11B NMR. Some boron hydrides, LiB2H7 and LiB4H9, are found to be possible intermediates in this reaction. Thermal dehydrogenation analyses including TPD/MS and TG suggest 6 successive decomposition steps upon heating to 500 °C. The compound emits THF, diborane, pentaborane(9) and hydrogen simultaneously below 170 °C and emits almost pure hydrogen at elevated temperature. LiBH4 is formed at 170 °C as one of the products and disappears at 400 °C. At least two kinds of other intermediates are found in the decomposition reaction, with one of them suspected to be Li2B12H12.
Co-reporter:Guoling Li, Li Li, Jialong Hao, Jie Zheng, Wenhuai Tian, Xingguo Li
Materials Letters 2016 Volume 176() pp:253-256
Publication Date(Web):1 August 2016
DOI:10.1016/j.matlet.2016.04.128
•The first time that the oxidation process of Tb can be displayed by NanoSIMS.•18O diffusion coefficient in Tb between 1.4×10−19 and 1.22×10−18 m2/s is proposed.•We detected the localized defects nucleation and uniform growth stage.High resolution secondary ion mass spectrometry (SIMS) analysis has been used to study the oxidation mechanisms when high purity terbium (Tb) metal is exposed to corroding environments containing 18O2 isotope. The diffusion coefficients for 18O in Tb at a natural atmosphere can be calculated, which plays an important role in subsequent purification and application in industry. Clear evidence has been shown for the characteristic distributions of 18O after the kinetic transitions. The migration behavior is correlated with the existence of defects in the metal which allow the corrosions occur as localized nucleation. A set of ionization model has been developed to describe the oxidation process.
Co-reporter:Zixu Tao, Teng Wang, Xiaojuan Wang, Jie ZhengXingguo Li
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 51) pp:
Publication Date(Web):December 2, 2016
DOI:10.1021/acsami.6b13411
Noble metal free electrocatalysts for water splitting are key to low-cost, sustainable hydrogen production. In this work, we demonstrate that metal–organic frameworks (MOFs) can be controllably converted into catalysts for the oxygen evolution reaction (OER) or the hydrogen evolution reaction (HER). The OER catalyst is composed of FeNi alloy nanoparticles encapsulated in N-doped carbon nanotubes, which is obtained by thermal decomposition of a trimetallic (Zn2+, Fe2+, and Ni2+) zeolitic imidazolate framework (ZIF). It reaches 10 mA cm–2 at the overpotential of 300 mV with a low Tafel slope of 47.7 mV dec–1. The HER catalyst consists of Ni nanoparticles coated with a thin layer of N-doped carbon. It is obtained by thermal decomposition of a Ni-MOF in NH3. It shows low overpotential of only 77 mV at 20 mA cm–2 with low Tafel slope of 68 mV dec–1. The above noble metal free OER and HER electrocatalysts are applied in an alkaline electrolyzer driven by a commercial polycrystalline solar cell. It achieves electrolysis efficiency of 64.4% at 65 mA cm–2 under sun irradiation of 50 mW cm–2. This practical application shows the promising prospect of low-cost and high-efficiency sustainable hydrogen production from combination of solar cells with high-performance noble metal free electrocatalysts.Keywords: electrocatalysis; hydrogen evolution; metal−organic frameworks; oxygen evolution; water splitting;
Co-reporter:Teng Wang, Xiaojuan Wang, Yang Liu, Jie Zheng, Xingguo Li
Nano Energy 2016 Volume 22() pp:111-119
Publication Date(Web):April 2016
DOI:10.1016/j.nanoen.2016.02.023
•Excellent catalytic performance for the hydrogen evolution reaction. The biphasic nanocrystalline Ni–Mo–N catalyst shows low overpotential very close to that of commercial Pt/C catalyst and very excellent stability in both acidic and alkaline electrolytes.•Combined merits for catalysis due to unique biphasic structure. The Ni–Mo–N catalyst is composed of homogeneously distributed nanocrystals of metallic Ni and Ni–Mo nitride, which combines the merits of high catalytic activity and good acid stability.The hydrogen evolution reaction (HER) is of critical importance for sustainable hydrogen production from water electrolysis. In this work, we report a highly efficient and stable noble metal free HER catalyst, which is composed of homogeneously distributed metallic Ni and NiMo4N5 nanocrystals. The biphasic nanocrystalline Ni–Mo–N catalyst shows very low overpotential (53 mV in 0.5 M H2SO4 and 43 mV in 1 M KOH, at current density 20 mA/cm2) and good stability for HER in both acidic and alkaline electrolytes, which is a promising low cost alternative for platinum based HER catalysts.
Co-reporter:Teng Wang, Yanru Guo, Zhenxing Zhou, Xinghua Chang, Jie Zheng, and Xingguo Li
ACS Nano 2016 Volume 10(Issue 11) pp:10397
Publication Date(Web):October 19, 2016
DOI:10.1021/acsnano.6b06259
Developing noble-metal-free catalysts for electrochemical hydrogen evolution reactions (HER) with superior stability in acid is of critical importance for large-scale, low-cost hydrogen production from water electrolysis. Herein, we report a highly efficient and stable noble-metal-free HER catalyst, which is composed of Ni and Mo2C nanocrystals supported on N-doped graphite nanotubes. This catalyst shows very low overpotential (65 mV in 0.5 M H2SO4 at a current density of 10 mA cm–2 with a Tafel plot of 67 mV/dec) and good stability for HER in acidic electrolyte, which is a promising noble-metal-free HER catalyst.Keywords: graphite nanotube; hydrogen evolution reaction; nitrogen doping; Ni−Mo catalyst; water splitting
Co-reporter:Huaiwei Zhang, Xinyao Zheng, Teng Wang, Xingguo Li
Intermetallics 2016 70() pp: 29-32
Publication Date(Web):March 2016
DOI:10.1016/j.intermet.2015.11.006
A simple method was developed for improving the hydrogen storage properties through adding nano Ni–Al compounds using as a stable catalyst to the La2Mg17 alloys by a PVD method. With the trace addition of the catalyst, hydrogen absorption and desorption rate are all substantially improved for the La–Mg based alloys. The alloys formation process has been determined, and the activity energy of the hydride dehydrogenation reaction before and after Ni–Al nanocrystalline addition was also calculated.
Co-reporter:Guoling Li, Li Li, Ruiying Miao, Wenhuai Tian, Shihong Yan, Xingguo Li
Vacuum 2016 Volume 125() pp:21-25
Publication Date(Web):March 2016
DOI:10.1016/j.vacuum.2015.12.003
•More than kinds of 20 impurity elements reduced from 1114 ppm to 63 ppm.•The concentration of O dropped to 1.8 ppm.•Metallic impurities pinning O inside the metal can be detected using SIMS.Ultra-high purification of terbium (Tb) by vacuum distillation and external getter was investigated. More than 20 kinds of impurity elements were analyzed by glow discharge mass spectrometry (GDMS) and inert gas analysis (IGA). The analysis results show that total impurities decrease from 1114 ppm to 63 ppm. High volatile metallic impurities such as Mg, Ca, Mn, Zn, and Tm can be reduced effectively after distillation. The oxygen (O) concentration can be decreased to 1.8 ppm after deoxidation process, which currently is one of the best results in the contemporary studies. The chemical driving force for deoxidation has been calculated in this paper. The different deoxidation results of Tb metal with various purity have been discussed in detail using the secondary ion mass spectroscopy (SIMS). Finally, a ultra-high purity Tb with low concentration of O can be obtained through vacuum distillation and external getter method.
Co-reporter:Teng Wang, Qianyu Zhou, Xiaojuan Wang, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 32) pp:16435-16439
Publication Date(Web):09 Jul 2015
DOI:10.1039/C5TA04001A
Pyrolysis of a Ni based metal organic framework in NH3 yields Ni nanoparticles with surface nitridation together with thin carbon coating layers. The subtle surface modification significantly improves the catalytic performance for the hydrogen evolution reaction (HER). The surface modified Ni nanoparticles show a low overpotential of only 88 mV at a current density of 20 mA cm−2, which is one of the most efficient HER catalysts based on metallic Ni reported so far. The results suggest that controlled pyrolysis of MOFs is an effective method to prepare highly efficient noble metal free HER catalysts.
Co-reporter:Junwen Zhou, Xiaosong Yu, Xinxin Fan, Xiaojuan Wang, Haiwei Li, Yuanyuan Zhang, Wei Li, Jie Zheng, Bo Wang and Xingguo Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8272-8275
Publication Date(Web):06 Mar 2015
DOI:10.1039/C5TA00524H
The particle size of an electrode material is known to play an essential role in its electrochemical performance in Li-ion batteries. In Li–S batteries, porous host materials are applied to store sulfur and suppress the escape of polysulfides; yet the particle size of the host as an important parameter remains largely unexplored. Herein we chose ZIF-8, a metal–organic framework (MOF) proved promising for sulfur storage, as the proof-of-concept prototype, and systematically synthesized five sets of ZIF-8 samples of different particle sizes (from <20 nm to >1 μm), using them as S@MOF cathodes. The results show that sulfur utilization increases monotonically with the decrease of ZIF-8 particle size (<20 nm: >950 mA h g−1 at 0.5 C), while the best cycling stability (75% over 250 cycles at 0.5 C) is achieved with a moderate size (∼200 nm).
Co-reporter:Xinghua Chang, Wei Li, Junfeng Yang, Li Xu, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 7) pp:3522-3528
Publication Date(Web):23 Dec 2014
DOI:10.1039/C4TA06334A
Plasma reactions are very effective in the preparation of both silicon and carbon materials. However, Si/C composites, which are highly attractive as the anode material in lithium ion batteries, are difficult to be prepared using plasma due to the strong tendency of silicon carbide (SiC) formation. Here we effectively inhibit the SiC formation by generating reactive Si and C species in separated plasma zones and by using a solid graphite carbon precursor. Homogeneous Si/C nanocomposites with excellent lithium storage performance are obtained by one step plasma deposition at room temperature, which retain a high capacity of 1760 and 1460 mA h g−1 after more than 400 cycles at a charge/discharge rate of 2.0 and 4.0 A g−1, respectively.
Co-reporter:Gongbiao Xin, Huiping Yuan, Lijun Jiang, Shumao Wang, Xiaopeng Liu and Xingguo Li
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 20) pp:13606-13612
Publication Date(Web):27 Apr 2015
DOI:10.1039/C5CP01897H
In this paper, the gaseous and electrochemical hydrogen storage properties of 200 nm Mg–Pd thin films with different morphologies have been investigated. The results show that Mg–Pd films become porous with the increase of substrate temperature. Porous Mg–Pd films exhibit superior gaseous and electrochemical hydrogen storage behaviors under mild conditions, including rapid hydrogen sorption kinetics, a large hydrogen storage amount, high electrochemical discharge capacity, and a fast hydrogen diffusion rate. The excellent behaviors of porous Mg–Pd films might be ascribed to the significantly shortened hydrogen diffusion paths and the large contact areas between the hydrogen gas and the solid Mg phases, which are elucidative for the development and applications of thick Mg–Pd films.
Co-reporter:Guoling Li, Li Li, Kai Fu, Chongyun Wang, Jie Zheng, Li Xu, Wenhuai Tian, Xingguo Li
Journal of Alloys and Compounds 2015 Volume 648() pp:29-33
Publication Date(Web):5 November 2015
DOI:10.1016/j.jallcom.2015.06.222
•Hydrogen can shuttle gadolinium freely at high temperature.•The concentration of O and N dropped to 30 ppm and 19 ppm, respectively.•The hydrogen content could finally decrease to 17 ppm.•Hydrogen, water and ammonia signals can be detected successfully.•This method is environment friendly and no other recontaminations.The removal of non-metallic impurities, especially oxygen and nitrogen, from the rare-earth metal gadolinium (Gd) is challenging, due to their strong affinity to Gd metal. Herein we present an effective approach to prepare high purity Gd via a novel hydrogen in-situ refining method. The final concentrations of oxygen and nitrogen could be reduced to 30 and 19 mass ppm, respectively. The changes of lattice parameters were derived from XRD; enthalpy values and gaseous speciation associated with the gas–solid physiochemical reactions were determined through a combination of DSC/MS measurements and thermodynamic calculations. The results show that oxygen and nitrogen can be efficiently removed by degassing Gd with dissolved hydrogen. The underlying mechanism for the refinement is discussed systematically in this paper.
Co-reporter:Xinghua Chang, Mi Peng, Junfeng Yang, Teng Wang, Yu liu, Jie Zheng and Xingguo Li
RSC Advances 2015 vol. 5(Issue 92) pp:75098-75104
Publication Date(Web):26 Aug 2015
DOI:10.1039/C5RA13459E
A light activated miniature formaldehyde sensor working at room temperature is fabricated by CdSO4 modified ZnO nanoparticles. The CdSO4 is deposited on the surface of the ZnO nanoparticles as a separated phase rather than doping into the lattice of ZnO. The Cd2+ and SO42− on the surface play a synergic effect for the high sensitivity to formaldehyde. The sensor shows high sensitivity to formaldehyde, with detection limit lower than 1 ppm while shows no response to ethanol and very weak response to acetone. With engineering efforts, a highly compact prototype formaldehyde sensor is obtained, which is very convenient for portable formaldehyde specific detection.
Co-reporter:Xinxin Fan, Junwen Zhou, Teng Wang, Jie Zheng and Xingguo Li
RSC Advances 2015 vol. 5(Issue 72) pp:58595-58599
Publication Date(Web):30 Jun 2015
DOI:10.1039/C5RA09981A
ZIF-8 shows complete opposite particle size effects on the adsorption kinetics for two different adsorbates. Smaller ZIF-8 particles favor fast I3− uptake in aqueous solution while larger, less defective ZIF-8 particles exhibit faster adsorption kinetics for gaseous H2, which suggests different adsorption mechanisms for the two adsorbates.
Co-reporter:Guoling Li, Li Li, Chao Yang, Wenhuai Tian, Xingguo Li
International Journal of Hydrogen Energy 2015 Volume 40(Issue 25) pp:7943-7948
Publication Date(Web):6 July 2015
DOI:10.1016/j.ijhydene.2015.03.054
•The concentration of O and N dropped to 6.4 ppm and 9 ppm, respectively.•It's the first time that the concentration of O in terbium reduces substantially by hydrogen thermodynamically.•The temperature distribution and the fluid flow were simulated with Stefan problem.•We detected hydrogen H I, HO+ and N2H2 optical lines successfully using an optical emission spectroscopy (OES).Terbium metal was melted by DC arc plasma using pure Ar and Ar + H2 mixture, respectively. The temperature distribution and the fluid flow during the melting process were simulated. Oxygen and nitrogen concentrations were examined by the inert gas fusion method. Experimental results show that the gaseous concentrations can be reduced more efficiently by hydrogen plasma arc melting (HPAM). Activated hydrogen atoms dissociated in high temperature plasma-arc probably take part in the refining reactions. The detailed behaviors of oxygen, nitrogen and hydrogen atoms are discussed systematically in this study.
Co-reporter:Junwen Zhou, Rui Li, Xinxin Fan, Yifa Chen, Ruodan Han, Wei Li, Jie Zheng, Bo Wang and Xingguo Li
Energy & Environmental Science 2014 vol. 7(Issue 8) pp:2715-2724
Publication Date(Web):03 Jun 2014
DOI:10.1039/C4EE01382D
Unlike an intercalation cathode, which has an intrinsic host structure made of redox metal sites allowing the transport of Li+/e−, sulfur as a conversion cathode requires an additional host to store and immobilize the mobile redox centers, polysulfides. Metal–organic frameworks (MOFs) as a class of highly porous and well-defined crystalline materials are a promising platform to search for an effective host through rational design. With the appropriate selection of an electrolyte and a cutoff voltage range, sulfur stored in an appropriate MOF host can take advantage of both intercalation (fast and stable) and conversion (high energy density) cathodes. Herein, we describe a fast cathode with long cycle life based on sulfur and ZIF-8 nanocrystals. With 30 wt% sulfur loading in the electrode, it achieves remarkable discharge capacities of 1055 mA h g−1 (based on sulfur) at 0.1 C and 710 mA h g−1 at 1 C. The decay over 300 cycles at 0.5 C is 0.08% per cycle, prominent in long-cycle Li–S batteries. By comparing with another three distinct MOFs, MIL-53 (Al), NH2-MIL-53 (Al) and HKUST-1, as well as two sets of ZIF-8 with particle sizes in the micrometer range, it reveals that (i) the small particle size of the MOF host is appreciable to achieve a high capacity and (ii) small apertures, associated with functionalities in the open framework that have affinity with the polysulfide anions, can help achieve a stable cycling. We believe that the findings are general and applicable for the rational design of new hosts for sulfur in other porous material families to produce more effective and stable Li–S batteries.
Co-reporter:Xiaojuan Wang, Junwen Zhou, He Fu, Wei Li, Xinxin Fan, Gongbiao Xin, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2014 vol. 2(Issue 34) pp:14064-14070
Publication Date(Web):24 Jun 2014
DOI:10.1039/C4TA01506A
Developing noble metal free catalysts for the oxygen reduction reaction (ORR) is of critical importance for the production of low cost polymer electrolyte membrane fuel cells. In this paper, metal organic frameworks (MOFs) are used as precursors to synthesize ORR catalysts via pyrolysis in an inert atmosphere. The ORR performance is found to be closely associated with the metal/ligand combination in MOFs. The Co-imidazole based MOF (ZIF-67) derived catalyst exhibits the best ORR activity in both alkaline and acidic electrolytes. The Co cations coordinated by the aromatic nitrogen ligands in ZIF-67 may assist the formation of ORR active sites in the derived catalyst. The best ORR performance is obtained when the porosity of the derived catalyst is maximized, by optimizing the pyrolysis temperature and the acid leaching process. The performance of the best MOF derived catalyst is comparable to that of Pt/C in both alkaline and acidic electrolytes.
Co-reporter:Wei Li, Jie Zheng, Tiankai Chen, Teng Wang, Xiaojuan Wang and Xingguo Li
Chemical Communications 2014 vol. 50(Issue 16) pp:2052-2054
Publication Date(Web):23 Dec 2013
DOI:10.1039/C3CC47719C
We employ a tandem plasma reaction method to prepare ultrafine Ge nanoparticles embedded in a carbon matrix in one step. The obtained Ge–C composite exhibits very high lithium storage capacity (980 mA h g−1) and excellent cycling performance (less than 2% capacity loss in 100 cycles).
Co-reporter:Xinxin Fan, Wei Wang, Wei Li, Junwen Zhou, Bo Wang, Jie Zheng, and Xingguo Li
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 17) pp:14994
Publication Date(Web):August 10, 2014
DOI:10.1021/am5028346
ZIF-8 nanocrystals with a sub-100 nm size are prepared by a surfactant mediated method in aqueous solution. Pure ZIF-8 phase can be obtained with a stoichiometric Zn/2-methylimidazole ratio. The surfactant mixture of Span 80 and Tween 80 may stabilize the Zn/2-methylimidazole coordination structure and prevent the formation of the hydroxide or alkaline salt. The nanocrystals maintain a high specific surface area of 1360 m2/g. The particle size effect on the adsorption kinetics of the ZIF-8 nanocrystals is studied by using two different probing molecules (I3– anion and Rhodamine B molecule). For the I3– anion, which is smaller than the aperture size of ZIF-8, the ZIF-8 nanoparticles exhibit faster absorption kinetics compared to the bulk material. For the Rhodamine B molecule, which is larger than the aperture size of ZIF-8, only surface adsorption occurs. The enhanced adsorption kinetics of the ZIF-8 nanoparticles is attributed to the smaller particles size, which reduces the intraparticle diffusion length. ZIF-8 nanocrystals prepared by a surfactant mediated method in aqueous solution exhibit faster adsorption kinetics compared to the bulk material.Keywords: aqueous solution; kinetics; nanocrystal; surfactant; ZIF-8
Co-reporter:He Fu, Junzhi Yang, Xiaojuan Wang, Gongbiao Xin, Jie Zheng, and Xingguo Li
Inorganic Chemistry 2014 Volume 53(Issue 14) pp:7334-7339
Publication Date(Web):June 27, 2014
DOI:10.1021/ic500679b
LiNH(BH3)NH2BH3, the first example of metal-substituted hydrazine bisborane (HBB), is synthesized via the reaction between HBB and n-butyllithium in ether solution. 11B NMR and Fourier transform infrared spectroscopy indicate a new structure, in which one of the N–H bonds is replaced by a N–Li bond. The X-ray diffraction pattern of the product also indicates the formation of a new crystal structure. This compound releases hydrogen at 126 and 170 °C with satisfactory purity and exhibits superior hydrogen storage properties compared with HBB. Differential scanning calorimetry measurement suggests the dehydrogenation reaction of this compound is less exothermic than that of HBB.
Co-reporter:Jianglan Qu, Yang Liu, Gongbiao Xin, Jie Zheng and Xingguo Li
Dalton Transactions 2014 vol. 43(Issue 15) pp:5908-5912
Publication Date(Web):31 Jan 2014
DOI:10.1039/C3DT53646G
Pd–Mg–Pd thin films with variable thickness of Mg layers were prepared. Their optical and electrical changes in both gasochromic and chemochromic processes were compared to investigate the kinetics of Mg-based thin films at room temperature. Hydrogen absorption and desorption kinetics of Pd–Mg–Pd thin films were strongly dependent on the thickness of the Mg layer. Especially, when the thickness was lowered to 60 nm, a MgH2 layer formed immediately after exposure to H2 at room temperature, while a Mg layer was rapidly generated during hydrogen desorption in ambient air. By means of optical and electrical resistance measurements, we found that the diffusion process contributed significantly to hydrogen absorption and desorption. The remarkable absorption and desorption kinetics at room temperature reported here suggested promising applications in Mg-based energy-efficient devices and hydrogen sensors.
Co-reporter:Gongbiao Xin, Yanyan Wang, He Fu, Guoling Li, Jie Zheng and Xingguo Li
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 7) pp:3001-3006
Publication Date(Web):09 Dec 2013
DOI:10.1039/C3CP54714K
In this paper, the structures of 500 nm thick Mg–Pd films were tailored by insertion of 1 nm thin Ti interlayers, and their electrochemical hydrogen storage properties were investigated. Results showed that thin Ti interlayers in the Mg bulk film could significantly improve the discharge properties of thick Mg–Pd films. The Mg100–Ti1 sample exhibited the most promising electrochemical properties, including a shorter activation period, larger discharge capacity, superior cyclic stability and high rate discharge capability, due to the creation of numerous interfaces and nucleation sites, reduction of the hydrogen diffusion path, and synergetic catalytic effects of Pd and Ti layers.
Co-reporter:Feng Tian, Guoling Li, Li Li, Zhiqiang Wang, Shihong Yan, Xingguo Li
Journal of Alloys and Compounds 2014 Volume 592() pp:176-184
Publication Date(Web):15 April 2014
DOI:10.1016/j.jallcom.2013.12.260
The principle and application of seven purification methods for metals in solid state are investigated. Ultra high vacuum degassing and external gettering can effectively remove interstitial impurities in refractory metals. Interstitial impurity can be decreased to very low level in fused halide salt at low temperature, especially when current flows through. Solid state electro-transport technology can remove both interstitial impurities and many metallic impurities. The application and limitation of solid state thermo-transport technology are also discussed.
Co-reporter:Yanyan Wang, Gongbiao Xin, Wei Li, Wei Wang, Chongyun Wang, Jie Zheng, Xingguo Li
International Journal of Hydrogen Energy 2014 Volume 39(Issue 9) pp:4373-4379
Publication Date(Web):18 March 2014
DOI:10.1016/j.ijhydene.2013.12.181
•Pd-capped binary Mg–Y thin films were prepared by magnetron co-sputtering.•Mg–Y films are intermetallic with ultrafine nanocrystalline structure.•Mg–Y films show superior electrochemical hydrogen storage properties.•Mg78Y22 film achieves a high discharge capacity about 1590 mAh g−1.Mg–Y thin films capped with Pd have been prepared by direct current magnetron co-sputtering system. It is found that Mg alloyed with Y in film state forms ultrafine nanocrystalline intermetallic compounds. The structure together with the catalytic effect of Y gives rise to a high electrochemical hydrogen storage capacities and superior activation properties. It is worthy to note that Mg78Y22 film achieves a high discharge capacity of 1590 mAh g−1 without requiring activation process. Moreover, Mg alloyed with Y effectively improves the cyclic stability of Mg-based films ascribing to the anti-corrosion role of Y. For Mg37Y63 film, more than 92％ of the maximum discharge capacity can be maintained after 100 charge–discharge cycles.
Co-reporter:Xiaojuan Wang, He Fu, Wei Li, Jie Zheng and Xingguo Li
RSC Advances 2014 vol. 4(Issue 71) pp:37779-37785
Publication Date(Web):13 Aug 2014
DOI:10.1039/C4RA05961A
Metal, N codoped nanoporous carbon (N–M–nC, M = Fe, Co) is prepared by in situ incorporation of the metal during the formation of the nanoporous carbon skeleton followed by NH3 treatment. The samples exhibit superior catalytic performance for the oxygen reduction reaction (ORR) in alkaline electrolytes. M, N codoping shows a synergic effect with improved ORR performance compared to the sample with only nitrogen dopant (N–nC), in the order of N–Fe–nC > N–Co–nC > N–nC, indicating that the M–N synergic effect is critical for high ORR performance in alkaline electrolyte. A detailed structural characterization of the catalysts is carried out, which suggests that the improved ORR performance should be attributed to the formation of active sites with M–N bonding. Other structural differences, including surface area, porosity and carbon structure, play a minor role. The performance of the N–Fe–nC sample is comparable to that of commercial Pt/C, including more positive onset and halfwave potential, comparable saturation current density and a dominant four-electron pathway, which suggests that nanoporous carbon can serve as an ideal platform for developing high performance ORR catalysts via proper doping.
Co-reporter:Wei Wang, Chongyun Wang, Teng Wang, Wei Li, Liangjie Chen, Ruqiang Zou, Jie Zheng, Xingguo Li
Materials Chemistry and Physics 2014 Volume 147(Issue 3) pp:701-706
Publication Date(Web):15 October 2014
DOI:10.1016/j.matchemphys.2014.06.009
•An effective way to enhance the thermal conductivity of microcapsules.•The reduced graphene oxide (rGO) sheets were prepared by different methods.•Low concentration of graphene results in notable increase of thermal conductivity.Reduced graphene oxide (rGO) sheets prepared by different methods are incorporated to boost the thermal conductivity of organic phase change materials (n-eicosane) in silica microcapsules. Low concentration (1 wt%) of graphene dosing already results in notable increase of the thermal conductivity. The preparation methods of rGO significantly affect the thermal properties of the composite. With 1 wt% dosing, sodium borohydride (NaBH4) reduced rGO increases the thermal conductivity by 83% and decrease the phase change enthalpy by 6%. On the other hand, the thermal reduced rGO increases the thermal conductivity by 193% but leads to a 15% loss of the phase enthalpy. The difference is attributed to the different surface morphology and functional groups of the rGO sheets.
Co-reporter:Jun Chen, He Fu, Yifu Xiong, Jinrong Xu, Jie Zheng, Xingguo Li
Nano Energy 2014 10() pp: 337-343
Publication Date(Web):
DOI:10.1016/j.nanoen.2014.10.002
Co-reporter:Jie Zheng, DengChen Yang, Wei Li, He Fu and Xingguo Li
Chemical Communications 2013 vol. 49(Issue 82) pp:9437-9439
Publication Date(Web):12 Aug 2013
DOI:10.1039/C3CC45021J
H2 generation from the reaction between Mg nanoparticles and water can be significantly promoted by low cost chlorides. The promotion effect exhibits strong correlation with the OH− affinity of the corresponding cation. This interesting observation offers a simple and effective solution to portable H2 generation under mild conditions.
Co-reporter:Tong Liu, Hailong Shen, Yang Liu, Lei Xie, Jianglan Qu, Huaiyu Shao, Xingguo Li
Journal of Power Sources 2013 Volume 227() pp:86-93
Publication Date(Web):1 April 2013
DOI:10.1016/j.jpowsour.2012.11.011
Different from conventional method, we have produced nanoparticles of Mg, Fe, Co, Ni, Cu and other metals by hydrogen plasma metal reaction (HPMR) in semi-industrial scale. Using these elemental nanoparticles as raw materials, nanostructured Mg-based compounds with high purity including Mg2Ni, Mg2Co, Mg2Cu and Mg2FeH6 are further synthesized by gas–solid reaction in much mild conditions. The Mg2Ni nanoparticles of 50 nm can be prepared at 523 K under 4 MPa H2. The formation mechanisms of the elemental nanoparticles during HPMR and the nanostructured Mg-based compounds during gas–solid reaction are discussed. The nanostructure of these samples greatly enhances the kinetic properties of hydrogen absorption and desorption. The Mg2Ni nanoparticles can absorb hydrogen and saturate at 0.95 H M−1 (the number of hydrogen atoms per metal atom) in several minutes at 493 K. The sorption kinetics of the nanostructured Mg2Ni is almost stable during ten cycles. The thermodynamic properties of these nanostructured Mg2M are improved slightly.Graphical abstractWe produced elemental metal nanoparticles by hydrogen plasma metal reaction (HPMR) in semi-industrial scale, and nanostructured Mg-based compounds with high purity by gas–solid reaction in much mild conditions. The nanostructure of these samples greatly enhanced the kinetic properties of hydrogen absorption and desorption. The thermodynamic properties of these nanostructured Mg2M are improved only slightly.Highlights► We prepared the nanostructured Mg-based compounds by gas–solid reaction. ► The nanostructure of these compounds greatly enhances the sorption kinetics. ► The Mg2Ni nanoparticles can absorb 0.95 H M−1 hydrogen in several minutes at 493 K ► The sorption kinetics of the nanostructured Mg2Ni is stable during ten cycles. ► The thermodynamic properties of these nanostructured Mg2M are improved slightly.
Co-reporter:Wei Li, Rong Yang, Xiaojuan Wang, Teng Wang, Jie Zheng, Xingguo Li
Journal of Power Sources 2013 Volume 221() pp:242-246
Publication Date(Web):1 January 2013
DOI:10.1016/j.jpowsour.2012.08.042
Si has a very high theoretical capacity of 4200 mAh g−1 as the anode materials for lithium ion batteries, which is near ten times higher than that of the current commercial graphite anode. However, it suffers from severe volume expansion/contraction during the charge/discharge processes, which is the main obstacle for its application. In this work, we prepare Si/C composite anodes with an intercalated Si/C multilayer structure by alternately depositing C and Si by plasma decomposition of C2H2 and magnetron sputtering of a Si target, respectively. Near theoretical capacity can be achieved (about 4000 mAh g−1) for more than 100 cycles for thin Si layers, which is attributed to the buffer effect of the carbon layers. This structure is also scalable up to multiple Si/C layers. A critical thickness of 20 nm is found for the silicon layer, below which the near theoretical capacity can be stably maintained. This critical thickness may shed light on future designs of nanostructured silicon anode with high capacity and stability for lithium ion batteries.Graphical abstractAn intercalated Si/C multilayer structure was used as the anode for Li-ion batteries. And near theoretical capacity can be achieved (about 4000 mAh g−1) for more than 100 cycles for thin Si layers.Highlights► A new method (novel dual plasma deposition approach) to deposit Si and C together. ► Near theoretical stable capacity can be achieved for Si layer. ► A critical thickness of 20 nm is found for the Si layer.
Co-reporter:Wei Wang, Chongyun Wang, Wei Li, Xinxin Fan, Zhonghua Wu, Jie Zheng and Xingguo Li
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 34) pp:14390-14395
Publication Date(Web):21 Jun 2013
DOI:10.1039/C3CP51875B
Silica microcapsules with hierarchical pore structure are prepared using a one step emulsion templated hydrolysis method. Silica particles of around 100 nm with percolated nanosized pores are self-assembled into micrometer scale spherical shells. The porous structure serves as an ideal host for shape stabilization of melted organic compounds. Small angle X-ray scattering (SAXS) results show that the n-eicosane encapsulated in nanoporous silica consists of mass fractal structure with a fractal dimension of 2.1. n-Eicosane encapsulated in the nanosized pores exhibits novel phase change behavior. A large melting point drop from 37.0 to 28.8 °C is observed, which is attributed to the strong interaction between the n-eicosane molecules and the silica skeleton.
Co-reporter:Gongbiao Xin, Xiaojuan Wang, Chongyun Wang, Jie Zheng and Xingguo Li
Dalton Transactions 2013 vol. 42(Issue 48) pp:16693-16696
Publication Date(Web):08 Oct 2013
DOI:10.1039/C3DT52482E
An alkaline primary Mg–air battery made from a porous Mg thin film displayed superior discharge performances, including a flat discharge plateau, a high open-circuit voltage of 1.41 V and a large discharge capacity of 821 mAh g−1, suggesting that the electrochemical performances of Mg–air batteries can be improved by controlling the Mg anode morphology.
Co-reporter:Tong Liu, Yurong Cao, Gongbiao Xin and Xingguo Li
Dalton Transactions 2013 vol. 42(Issue 37) pp:13692-13697
Publication Date(Web):05 Jul 2013
DOI:10.1039/C3DT51628H
The MgxNi100−x films of 100 nm have been prepared by magnetron co-sputtering Mg and Ni targets, and a Pd layer of 10 nm was deposited on these films by magnetron sputtering a Pd target. Mg2Ni and MgNi2 are directly generated during the co-sputtering process in the Mg84Ni16/Pd and Mg48Ni52/Pd films. The hydrogen storage properties of the films under 0.1 MPa H2 at 298 K were investigated. The hydrogenation of the Mg84Ni16/Pd film saturates within 45 s and exhibits the faster absorption kinetics compared with Mg94Ni6/Pd and Mg48Ni52/Pd films. The electrochemical properties of the MgxNi100−x/Pd films were investigated in 6 M KOH with a three-electrode cell. The Mg84Ni16/Pd film can be activated just at the first cycle. The maximum discharge capacity of the Mg84Ni16/Pd film is 482.7 mAh g−1, the highest among these films.
Co-reporter:Gongbiao Xin, Junzhi Yang, He Fu, Jie Zheng, Xingguo Li
International Journal of Hydrogen Energy 2013 Volume 38(Issue 25) pp:10625-10629
Publication Date(Web):21 August 2013
DOI:10.1016/j.ijhydene.2013.06.075
•Different Pd capped MgxTi1−x films are prepared.•Mg0.85Ti0.15 and Mg0.72Ti0.28 show promising properties.•The maximum capacity of Mg0.85Ti0.15 film is ∼1100 mAh g−1.•80% of the capacity can be maintained after 150 cycles.•They can be competitive candidates as anode materials.Pd capped MgxTi1−x films have been prepared by magnetron sputtering, and their electrochemical hydrogen storage properties have been investigated. Results show that the Mg0.85Ti0.15 and Mg0.72Ti0.28 samples exhibit the most promising electrochemical properties, including short activation period, large discharge capacities, excellent cyclic stabilities and superior anti-corrosion behaviors. The maximum capacity of Mg0.85Ti0.15 film is achieved to ∼1100 mAh g−1 after 30 cycles, 80% of which (∼810 mAh g−1) can be maintained even after 150 cycles. Such excellent properties make Pd capped MgxTi1−x films competitive candidates as anode materials of alkaline secondary batteries.Pd capped MgxTi1−x films exhibit promising electrochemical properties, showing potential applications in negative electrodes of alkaline secondary batteries.
Co-reporter:Gongbiao Xin, Junzhi Yang, He Fu, Wei Li, Jie Zheng and Xingguo Li
RSC Advances 2013 vol. 3(Issue 13) pp:4167-4170
Publication Date(Web):24 Jan 2013
DOI:10.1039/C3RA21431A
500 nm thick Mg–Pd films with different structures were prepared and their hydrogen storage properties were investigated. Results indicated that thin Ti interlayers in the Mg bulk film could significantly improve the hydrogen sorption kinetics and reversibility, offering an effective way to improve the hydrogen storage properties of thick Mg-based films.
Co-reporter:Wei Li, Rong Yang, Jie Zheng, Xingguo Li
Nano Energy 2013 Volume 2(Issue 6) pp:1314-1321
Publication Date(Web):November 2013
DOI:10.1016/j.nanoen.2013.06.012
•New apporach to prepare Sn/C binary nanocomposites in which particle size of Sn and the content of carbon can be accurately controlled.•The obtained composites exhibits very high reversible capacity (up to 850 mAh g−1 of the Sn component).•A systematic study on the correlation between the electrode performance and the structure parameters (the Sn particle size and the carbon layer thickness).The Sn/C nanocomposites are of great interest as high capacity anode materials for lithium ion batteries (LIBs). In this paper, we employ a tandem plasma reaction method for controlled preparation of Sn/C binary composites. The Sn and C components are generated by magnetron sputtering and plasma decomposition of CH4 in two tandem plasma zones, respectively. The obtained Sn/C composites are composed of ultrafine Sn particles homogeneously embedded in carbon matrix, which exhibit very high reversible lithium storage capacity. The tandem plasma reaction method offers great versatility in controlling the Sn/C ratio and the Sn particle size, allowing a systematic study on the relationship between the structural parameters and the electrode performance. The reversible anode capacity is found to be strongly affected by the Sn particle size while it shows a much weaker correlation with the carbon coating layer.A tandem plasma reaction method enables controlled preparation of Sn/C composites for LIB anode application, allowing a systematic study on the correlation between the reversible capacity and the structural parameters. The results suggest that reducing the Sn particle size is beneficial for attaining high reversible capacity. The carbon layer thickness, on the other hand, shows a much weaker correlation with the reversible capacity.
Co-reporter:Tong Liu, Chenggong Qin, Tongwen Zhang, Yurong Cao, Mu Zhu and Xingguo Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 37) pp:19831-19838
Publication Date(Web):03 Aug 2012
DOI:10.1039/C2JM33911K
In order to improve the hydrogen storage properties of Mg, Mg@Mg17Al12 ultrafine particles (UFPs) with 7, 22 and 27 at% Al have been successfully prepared by a hydrogen plasma–metal reaction (HPMR) approach. These UFPs are nearly spherical in shape with an average size of about 150 nm. The Mg particle core is a single crystal, and the Mg17Al12 particle shell of 2–5 nm thickness effectively suppresses the formation of MgO. The formation mechanism of the core–shell structure is interpreted in terms of Mg–Al phase transformation. The Mg17Al12 shell disproportionates into MgH2 and Al upon hydrogenation, and is recovered after hydrogen release. The morphology and size of these UFPs are not obviously changed during the sorption cycle, whereas the Mg particle core changes from single crystal into the polycrystalline form of 2–4 nm size. The hydrogen sorption kinetics and storage capacity of the Mg@Mg17Al12 UFPs decreased with increasing Al content. Mg–7 at.% Al can absorb 5.7 wt% H2 at 523 K and 7.0 wt% H2 at 673 K. It can release 6.0 wt% H2 within 30 minutes at 623 K and 6.2 wt% H2 within 3 minutes at 673 K. The catalytic effect and oxidation resistance of the Mg17Al12 shell, and the nanostructure of the Mg core accelerate the hydrogen diffusion, with low hydrogen absorption and desorption activation energies of 49.3 and 105.5 kJ mol−1, respectively.
Co-reporter:Tong Liu, Chenggong Qin, Mu Zhu, Yurong Cao, Hailong Shen, Xingguo Li
Journal of Power Sources 2012 Volume 219() pp:100-105
Publication Date(Web):1 December 2012
DOI:10.1016/j.jpowsour.2012.07.027
Mg-2 at.% La-2.6 at.% Al composite nanoparticles are prepared by hydrogen plasma–metal reaction (HPMR) method. The electron microscopy and X-ray diffraction studies reveal that these nanoparticles are made of single crystalline Mg of about 160 nm, and a little amount of polycrystalline Al2La of 15 nm dispersing on the surface of Mg. The addition of Al effectively reduces the oxidation of Mg nanoparticles. After hydrogenation, Al2La disproportionates into single crystalline LaH3 of 15 nm. The composite nanoparticles can absorb 5.0 wt.% H2 in 30 min even at 473 K, and the storage capacity is as high as 6.8 wt.% at 673 K. They can also release 6.0 wt.% H2 in less than 10 min at 673 K. The catalytic effect of LaH3 nanoparticles, nanocrystalline structure and low oxide content of Mg accelerate the hydrogen sorption process of Mg–La–Al composite nanoparticles with a low hydrogen absorption activation energy of 23.1 kJ mol−1.Highlights► We prepared Mg–La–Al composite nanoparticles by hydrogen plasma–metal reaction. ► These composite nanoparticles can absorb 5.0 wt.% hydrogen in 30 min at 473 K ► The hydrogen absorption activation energy is as low as 23.1 kJ mol−1. ► The LaH3 nanoparticle and the nanostructured Mg improve the sorption process.
Co-reporter:Ping Song, Bin Liu, Yaoqi Li, Junzhi Yang, Zheming Wang and Xingguo Li
CrystEngComm 2012 vol. 14(Issue 6) pp:2296-2301
Publication Date(Web):27 Jan 2012
DOI:10.1039/C2CE05586D
Two new metal–organic frameworks (MOFs) [Co2(btec)(bipy)2(DMF)]·DMF·3H2O (1) (btec = 1,2,4,5-benzenetetracarboxylate; bipy = 4,4′-bipyridine; DMF = N,N′-dimethylformamide) and Co2(btec)(bipy)(DMF)2 (2) were synthesized with the same starting materials under different solvothermal conditions. The higher temperature favors the generation of compound 2, while the slightly lower temperature with the higher bipy ratio leads to the porous structure of compound 1. Their structures are determined by single-crystal X-ray diffractions. Compound 1 is a 3D pillared-layer framework with interconnected channels along two directions after the removal of free guest molecules. The BET (Brunauer–Emmett–Teller) surface area of 1 was calculated to be 596 m2 g−1 by nitrogen adsorption at 77 K. The hydrogen adsorption isotherm at 77 K shows an excess uptake of 1.1 wt% at 15 bar. The heat (Qst) of hydrogen adsorption was estimated to be 7.3 kJ mol−1 at zero coverage. In compound 2, the wave-like layers constructed with btec are further pillared by bipy, giving rise to the 3D framework with the 1D channels occupied by coordinated DMF molecules.
Co-reporter:Gongbiao Xin, Junzhi Yang, Guoqing Zhang, Jie Zheng and Xingguo Li
Dalton Transactions 2012 vol. 41(Issue 38) pp:11555-11558
Publication Date(Web):21 May 2012
DOI:10.1039/C2DT30946G
We prepared a series of nano-sized Mg–Al–Pd trilayer films and investigated their hydrogen storage properties under mild conditions. Results showed that Al 1 nm sample had the best absorption kinetics and excellent optical properties at room temperature, making it a promising candidate for hydrogen sensors and smart windows.
Co-reporter:Gongbiao Xin, Junzhi Yang, Chongyun Wang, Jie Zheng and Xingguo Li
Dalton Transactions 2012 vol. 41(Issue 22) pp:6783-6790
Publication Date(Web):19 Mar 2012
DOI:10.1039/C2DT30253E
In this paper, a series of Mg–Ti–Pd trilayer films with various thicknesses of the Ti interlayer were prepared by magnetron sputtering. The trilayer films could be reversibly (de)hydrogenated at room temperature. The relationship between structure and properties of Mg–Ti–Pd trilayer films was comprehensively investigated. Our studies showed that the hydrogen storage properties of Mg–Pd films were significantly improved with the addition of a Ti interlayer. The optimal hydrogenation properties were obtained when the Ti interlayer was 1 nm. The superior hydrogenation properties achieved by introduction of the Ti interlayer could be attributed to several aspects: prevention of Mg–Pd alloying; catalytic dissociation of H2 molecules and provision of heterogeneous nucleation sites. These results were elucidative for the development of high performance intermetallic hydrogen storage materials and thin film based functional devices.
Co-reporter:Chongyun Wang, Lili Feng, Huazhe Yang, Gongbiao Xin, Wei Li, Jie Zheng, Wenhuai Tian and Xingguo Li
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 38) pp:13233-13238
Publication Date(Web):06 Aug 2012
DOI:10.1039/C2CP41988B
Graphene oxide (GO) sheets were introduced to stabilize the melted polyethylene glycol (PEG) during the solid–liquid phase change process, which can be used as a smart heat storage system. The structural properties and phase change behaviors of the PEG–GO composites were comprehensively investigated as a function of the PEG content by means of various characterization techniques. The highest stabilized PEG content is 90 wt% in the composites, resulting in a heat storage capacity of 156.9 J g−1, 93.9% of the phase change enthalpy of pure PEG. Notably, GO has much stronger impact on lowering of the phase change temperature of PEG compared with some other porous carbon materials (activated carbon and ordered mesoporous carbon) due to the unique thin layer structure of GO. Because of the high heat storage capacity and the moderate phase change temperature, the PEG–GO composite is a promising heat energy storage candidate at mild temperature.
Co-reporter:Junzhi Yang, Dichen Li, He Fu, Gongbiao Xin, Jie Zheng and Xingguo Li
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 8) pp:2857-2863
Publication Date(Web):21 Dec 2011
DOI:10.1039/C2CP23776H
Nano-composites of LiNH2–LiH–xMg(BH4)2 (0 ≤ x ≤ 2) were prepared by plasma metal reaction followed by a nucleation growth method. Highly reactive LiNH2–LiH hollow nanoparticles offered a favorable nucleus during a precipitation process of liquid Mg(BH4)2·OEt2. The electron microscopy results suggested that more than 90% of the obtained nano-composites were in the range 200–400 nm. Because of the short diffusion distance and ternary mixture self-catalyzing effect, this material possesses enhanced hydrogen (de)sorption attributes, including facile low-temperature kinetics, impure gases attenuation and partial reversibility. The optimal hydrogen storage properties were found at the composition of LiNH2–LiH–0.5Mg(BH4)2, which was tentatively attributed to a Li4(NH2)2(BH4)2 intermediate. 5.3 wt% hydrogen desorption could be recorded at 150 °C, with the first 2.2 wt% release being reversible. This work suggests that controlled in situ hybridization combined with formula optimization can improve hydrogen storage properties.
Co-reporter:Huazhe Yang, Lili Feng, Chongyun Wang, Wei Zhao, Xingguo Li
European Polymer Journal 2012 Volume 48(Issue 4) pp:803-810
Publication Date(Web):April 2012
DOI:10.1016/j.eurpolymj.2012.01.016
PEG/SiO2 shape-stabilized phase change materials with various mass fractions and molecular weights of PEG were prepared by the sol–gel method. Polyethylene glycol (PEG) and tetraethyl orthosilicate (TEOS) were chosen as the phase change substance and the silica framework precursor, respectively. The as-prepared samples were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM) techniques. It is shown that the silica framework strongly confined the crystallization of PEG. The crystallinity and thermodynamic performance of the composites were undesirable for PEG with molecular weight of 1500 even when the PEG content reached 80 wt%. The crystallinity and thermodynamic performances of the PEG/SiO2 composites first decline then improve with the increase of the PEG molecular weights, owing to the different confinement behaviors of the silica framework. Finally, we investigated the phase change mechanism of the PEG/SiO2 composites under the different confinement of the silica framework.Graphical abstractHighlights► PEG/SiO2 composites with various contents and Mw of PEG were obtained. ► Silica framework strongly confined the crystallization of PEG. ► Crystallinity and thermodynamic performances of the composites were investigated. ► Phase change mechanism of the PEG/SiO2 composites was clarified.
Co-reporter:Gongbiao Xin;Junzhi Yang;Wei Li;Jie Zheng
European Journal of Inorganic Chemistry 2012 Volume 2012( Issue 34) pp:5722-5728
Publication Date(Web):
DOI:10.1002/ejic.201200752
Abstract
A method to prepare well-dispersed metal nanoparticles on mesoporous substrates has been developed that uses a magnetron sputtering technique. Pd, Ni, and Pt nanoparticles are deposited on MCM-48, a silica-based mesoporous material, with good dispersion. The samples prepared by this method showed promising catalytic effects on the thermodynamic and kinetic properties of ammonia–borane (AB) thermal dehydrogenation. Catalyst-doped AB samples started to release H2 at much lower temperatures and suppressed the emission of volatile byproducts effectively. Furthermore, foaming and volume expansion can be totally avoided. The excellent catalytic performance is due to the synergetic effect of nanoconfinement of MCM-48 and the catalytic behavior of the metal particles.
Co-reporter:Junzhi Yang, He Fu, Ping Song, Jie Zheng, Xingguo Li
International Journal of Hydrogen Energy 2012 Volume 37(Issue 8) pp:6776-6783
Publication Date(Web):April 2012
DOI:10.1016/j.ijhydene.2012.01.109
The Mg(BH4)2-xLiH (0.1 ≤ x ≤ 0.8) composites which exhibit favorable dehydrogenation and encouraging reversibility are experimentally investigated. LiH additive reduces the onset temperature for dehydrogenation to 150 °C. And hydrogen release exceeds 10 wt.% from the new binary material below 250 °C. Furthermore, rehydrogenation results show that 3.6 wt.% hydrogen can still be recharged after twenty cycles at 180 °C. It should be emphasized that the long-term reversibility of borohydride under 200 °C is long overdue. TPD, PCT, and high-pressure DSC measurements are used to characterize the improvements in thermodynamic and kinetic ways. In addition, FT-IR and NMR studies indicate that the composite has a significant synergistic effect during (de)hydrogenation processes. This work suggests that controlled cation stoichiometry combined with doping by metal Li+ subvalent to Mg2+ facilitate the formation of polyborane intermediates [B3H8]− and [B2H6]2−. They improve the dehydrogenation properties and make the material reversible under mild conditions.LiH additive reduces the onset temperature for dehydrogenation to 150 °C. And hydrogen release exceed 10 wt.% below 240 °C. Furthermore, 3.6 wt.% hydrogen can be recharged after twenty cycles at 180 °C. Controlled cation stoichiometry combined with doping by metal Li+ subvalent to Mg2+ facilitates the formation of polyborane intermediates [B3H8]− and [B2H6]2−.Highlights► Mg(BH4)2–LiH composite shows favorable dehydrogenation and proper reversibility. ► The dehydrogenation starts at 150 °C, with over 10 wt % H2 release. ► The reversible amount of hydrogen is 3.6 wt % after twenty cycles at 180 °C. ► Enthalpy and activation energy changes indicate the lattice aberrance. ► Controlled substitution facilitates the formation of polyborane intermediates.
Co-reporter:Guoqing Zhang, Junzhi Yang, He Fu, Jie Zheng, Yan Li, Xingguo Li
Computational Materials Science 2012 Volume 54() pp:345-349
Publication Date(Web):March 2012
DOI:10.1016/j.commatsci.2011.10.037
Ca(BH4)2·2NH3 is considered to be a promising candidate for hydrogen storage. First-principles calculations based on density functional theory (DFT) were performed to study the structural and electronic properties. The optimized crystal structure was determined to be an orthorhombic Pbcn structure, with all atomic positions fully relaxed. The corresponding densities of states and charge densities indicated that strong correlations occur between Ca–B, B–H and N–H, but not between B–N, which obviously excluded the combination of calcium hydride and ammonia borane as the alternative structure. The presence of partial N–H⋯H–B dihydrogen bonding was verified. The calculated band structures implied an indirect wide band gap of 5.85 eV. The Bader charge analysis and calculated hydrogen removal energies were further investigated to explain the improved dehydrogenation properties of Ca(BH4)2·2NH3 compared to pristine Ca(BH4)2.Graphical abstractThe optimized crystal structure of Ca(BH4)2·2NH3 was determined to be an orthorhombic Pbcn structure, with the internal coordination environment was regarded. It is a promising candidate for hydrogen storage.Highlights► The crystal structure of Ca(BH4)2·2NH3 was determined with all atomic positions fully relaxed. ► The presence of N–H⋯H–B dihydrogen bonding was verified. ► Bader charge and hydrogen removal energies were calculated. ► The dehydrogenation performance was correlated with the intrinsic crystal structure and the electronic properties.
Co-reporter:Jie Zheng, Rong Yang, Yu Lou, Wei Li, Xingguo Li
Thin Solid Films 2012 Volume 521() pp:137-140
Publication Date(Web):30 October 2012
DOI:10.1016/j.tsf.2012.02.018
In2O3 thin films with vertically aligned blade like structure are prepared at low temperature of 300 °C by plasma enhanced chemical vapor deposition using InCl3, O2 and H2 as the precursors. The nanoscale morphology can be controlled by the H2 flow in the reaction system. Vertically aligned nanoblades with smooth surface can be obtained by directly reacting InCl3 with O2. Increasing the H2 fraction in the reaction system will causes secondary growth on the blade surface and finally leads to destruction of the blade like structure. Optical emission spectroscopy suggests that the morphology evolution induced by H2 addition can be attributed to the enhanced InCl3 dissociation and the suppressed etching effect of atomic Cl. The nanoblade In2O3 thin films exhibit superior lithium storage properties with a high stable capacity of 580 mAh⋅g− 1 up to 100 cycles, which is attributed to the well separated thin blade like nanostructure.
Co-reporter:Huaiyu Shao, Gongbiao Xin, Jie Zheng, Xingguo Li, Etsuo Akiba
Nano Energy 2012 Volume 1(Issue 4) pp:590-601
Publication Date(Web):July 2012
DOI:10.1016/j.nanoen.2012.05.005
Mg-based materials are very promising for hydrogen storage applications. However, both the kinetic and thermodynamic problems are remaining for these applications especially for on-board storage. Here we will review the methods used by the authors to synthesize Mg-based hydrogen storage materials with nanostructure as well as some novel techniques from other researchers, and focus on how these nanotechnology processing methods could change kinetics and thermodynamics in Mg-based materials for hydrogen storage. These methods include ball milling (mechanical grinding, mechanical alloying, reactive ball milling), thin film synthesis, hydrogen plasma metal reaction, catalyzed solution synthesis etc.Graphical abstractHighlights► Nano-processing methods for Mg-based hydrogen storage materials were reviewed. ► Lowest temperature for Mg-based materials to absorb hydrogen was reported. ► Effect of nano-processing methods on kinetics and thermodynamics was studied. ► Kinetics can be enhanced by nanotechnology and catalyst. ► Desorption thermodynamics does not change with nanosize above 5 nm.
Co-reporter:Tong Liu, Tongwen Zhang, Chenggong Qin, Mu Zhu, Xingguo Li
Journal of Power Sources 2011 Volume 196(Issue 22) pp:9599-9604
Publication Date(Web):15 November 2011
DOI:10.1016/j.jpowsour.2011.07.078
The Mg–10.2 at.% V nanoparticles are prepared by hydrogen plasma–metal reaction (HPMR) method. These nanoparticles are made of Mg, VH2 and a small amount of MgH2. The Mg nanoparticles are hexagonal in shape with the particle size in the range of 50–150 nm. The VH2 nanoparticles are spherical in shape with the particle size around 10 nm, and disperse on the surface of the Mg nanoparticles. After the hydrogen absorption, the mean particle size of MgH2 decreases to 60 nm, while the V nanoparticles are still about 10 nm. The Mg–V composite nanoparticles can absorb 3.8 wt.% hydrogen in less than 30 min at 473 K and accomplish a high hydrogen storage capacity of 5.0 wt.% in less than 5 min at 623 K. They can release 4.0 wt.% hydrogen in less than 15 min at 573 K. The catalytic effect of the V nanoparticles and the nanostructure and the low oxide content of the Mg particles promote the hydrogen sorption process with the low hydrogen absorption activation energy of 71.2 kJ mol−1.Highlights► We have prepared Mg–V composite nanoparticles by hydrogen plasma–metal reaction. ► These nanoparticles show high hydrogen sorption rate and storage capacity. ► The catalytic V nanoparticles and the nanostructured Mg promote the sorption process.
Co-reporter:Wei Li, Yanli Guo, Peng He, Rong Yang, Xingguo Li, Ye Chen, Dehai Liang, Masatoshi Kidowaki and Kohzo Ito
Polymer Chemistry 2011 vol. 2(Issue 8) pp:1797-1802
Publication Date(Web):06 May 2011
DOI:10.1039/C1PY00081K
Ethyl carbamylated polyrotaxane (ECPR) and propyl carbamylated polyrotaxane (PCPR) were prepared based on the reactions between ethyl/propyl isocyanate and polyrotaxane (PR) in anhydrous DMSO under an argon atmosphere. By changing the alkyl type and substitution ratio, the PR derivative with good water-solubility was obtained and its solutions showed reversible sol–gel phase transition. During the heating process, transition temperature from sol to gel decreased from 32 °C to 18 °C with increasing the solution concentration from 2.44% to 13.5%, while in the cooling process, all the gels with various concentration did not turn into sols until the temperature decreased to 1 °C, exhibiting large hysteresis between heating and cooling.
Co-reporter:Ping Song, Yaoqi Li, Wei Li, Bei He, Junzhi Yang, Xingguo Li
International Journal of Hydrogen Energy 2011 Volume 36(Issue 17) pp:10468-10473
Publication Date(Web):August 2011
DOI:10.1016/j.ijhydene.2011.05.120
A Co (0) catalyst is synthesized by the reduction of a metal-organic framework (MOF) precursor Co2(bdc)2(dabco) (bdc = 1,4-benzenedicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane). The amorphous catalyst exhibits highly efficient activity in the hydrolysis of ammonia borane (AB). The dehydrogenation of a 0.32 M aqueous AB solution completes in 1.4 min under room temperature. The porous structure in the MOF is proposed to play a key role. The catalytic effective Co (0) sites are stabilized by the organic molecules, which used to coordinate to Co (II) in the MOF precursor. This work implies that MOFs, with their large surface area and ample pore structures, may serve as ideal precursors for highly efficient heterogeneous catalysts.Highlights► The catalyst is synthesized by reduction from a metal-organic framework. ► The hydrolysis of ammonia borane is completed within 1.4 min at room temperature. ► The Co (0) sites are dispersed in the residue of the framework. ► The MOF based catalysts have much more broader applications.
Co-reporter:Tong Liu, Tongwen Zhang, Xuanzhou Zhang, Xingguo Li
International Journal of Hydrogen Energy 2011 Volume 36(Issue 5) pp:3515-3520
Publication Date(Web):March 2011
DOI:10.1016/j.ijhydene.2010.12.049
Mg-6.9 at.% Zn ultrafine particles (UFPs) were prepared by hydrogen plasma-metal reaction (HPMR) method. The electron microscopy study revealed that they were spherical in shape with particle size in the range 100–700 nm. Each fine particle was composed of single crystal structure of α-Mg(Zn) solid solution and amorphous structure of Mg–Zn alloy. After one absorption and desorption cycle, these UFPs transformed from the single crystal into the nanocrystalline structure and the mean particle size changed from 400 to 250 nm. It was found that the Mg–Zn UFPs could absorb 5.0 wt.% hydrogen in 20 min at 573 K and accomplish a high hydrogen storage capacity of 6.1 wt.% at 573 K. The fine particle size, nanocrystalline structure and the low oxide content of the obtained sample promoted the hydrogen sorption process with low hydrogen absorption activation energy of 56.3 kJ/mol. The enhanced hydrogen sorption properties of high absorbing rate and high storage capacity were due to the improved kinetics rather than the change in enthalpy.
Co-reporter:Xuanzhou Zhang, Rong Yang, Junzhi Yang, Wei Zhao, Jie Zheng, Wenhuai Tian, Xingguo Li
International Journal of Hydrogen Energy 2011 Volume 36(Issue 8) pp:4967-4975
Publication Date(Web):April 2011
DOI:10.1016/j.ijhydene.2010.12.052
In this work, we developed a method to prepare ultrafine Mg nanoparticles around 40 nm by acetylene plasma metal reaction, which is a revised approach for the traditional hydrogen plasma metal reaction. During the preparation, the growth of the Mg nanoparticles was confined by the carbon from the decomposition of acetylene. The size of the Mg particles exhibited a clear decreasing trend with increasing acetylene fraction in the plasma. Due to the short diffusion distance and large specific surface area, the kinetics of hydrogenation and dehydrogenation of the small Mg nanoparticles were improved. From the equilibrium plateau pressures of the absorption and desorption isotherms, the enthalpy and entropy of the reaction were deduced, which were significantly reduced compared to the commercial magnesium.Highlights► Acetylene was introduced into the arc plasma to control the growth of Mg particles. ► Mg nanoparticles around 40 nm were prepared by acetylene plasma metal reaction. ► The Mg particle size reduced with increasing the concentration of acetylene. ► The activation energy for the absorption and desorption of Mg were reduced. ► The reaction enthalpy and entropy were reduced.
Co-reporter:Ping Song, Yaoqi Li, Bei He, Junzhi Yang, Jie Zheng, Xingguo Li
Microporous and Mesoporous Materials 2011 Volume 142(Issue 1) pp:208-213
Publication Date(Web):June 2011
DOI:10.1016/j.micromeso.2010.12.001
The hydrogen storage properties of two pillared-layer metal-organic frameworks of Ni2(BTEC)(bipy)3·3DMF·2H2O (1) and Ni2(BDC)2(dabco)·4DMF·1.5H2O (2) (BTEC = 1,2,4,5-benzenetetracarboxylate; bipy = 4,4′-bipydine; BDC = 1,4-benzenedicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane; DMF = N,N′-dimethylformamide) were investigated. Compound 1 and 2 show a total hydrogen capacity of 1.78 and 3.96 wt.% at 77 K, respectively. Compound 2 exhibits a total hydrogen uptake of 0.81 wt.% at 299 K and 60 bar. At zero coverage, the heat of hydrogen adsorption of 1 and 2 is calculated to be 7.08 and 5.83 kJ/mol, respectively. The impacts of metal ions, pore structures, and surface areas on the hydrogen storage properties are discussed. Distorted aromatic pore structures introduced by multi-coordination ligands such as BTEC are proposed to be favorable to increase the hydrogen adsorption heats. The activated conditions and the stability in air of MOF samples are also concerned here.Graphical abstractResearch highlights► Ni2(BTEC)(bipy)3 and Ni2(BDC)2(dabco) show a total hydrogen capacity of 1.78 and 3.96 wt% at 77 K, respectively. ► Ni2(BDC)2(dabco) exhibits a hydrogen uptake of 0.81 wt% at 299 K and 60 bar. ► At zero coverage, the heat of hydrogen adsorption is calculated to be 7.08 and 5.83 kJ/mol, respectively.
Co-reporter:Rong Yang, Jie Zheng, Wei Li, Jianglan Qu, Xuanzhou Zhang, Xingguo Li
Materials Chemistry and Physics 2011 Volume 129(Issue 3) pp:693-695
Publication Date(Web):3 October 2011
DOI:10.1016/j.matchemphys.2011.05.027
The thermodynamically forbidden reaction between ZnCl2 and O2 was able to take place by using oxygen plasma, yielding cone-shaped ZnO nanostructure. In situ optical emission spectroscopy was used to identify the excited species during the plasma enhanced reaction. The determination of excited temperature suggested that the addition of O2 had great contribution to the enhanced dissociation of ZnCl2. The successful synthesis of ZnO indicates that the chlorides may replace the organometallics as a new precursor in thin film preparation industry.Graphical abstractHighlights► The thermodynamically forbidden reaction took place with the assistance of plasma. ► The reaction temperature was significantly decreased due to plasma activation. ► O2 had a great contribution to the excitation of chloride precursor. ► Chloride precursor has the potential applications to replace organometallics in PECVD.
Co-reporter:Lili Feng, Jie Zheng, Huazhe Yang, Yanli Guo, Wei Li, Xingguo Li
Solar Energy Materials and Solar Cells 2011 95(2) pp: 644-650
Publication Date(Web):
DOI:10.1016/j.solmat.2010.09.033
Co-reporter:Lili Feng, Wei Zhao, Jie Zheng, Sarah Frisco, Ping Song, Xingguo Li
Solar Energy Materials and Solar Cells 2011 95(12) pp: 3550-3556
Publication Date(Web):
DOI:10.1016/j.solmat.2011.08.020
Co-reporter:Jie Zheng;Rong Yang;Lei Xie;Jianglan Qu;Yang Liu
Advanced Materials 2010 Volume 22( Issue 13) pp:1451-1473
Publication Date(Web):
DOI:10.1002/adma.200903147
Abstract
Plasma is a unique medium for chemical reactions and materials preparations, which also finds its application in the current tide of nanostructure fabrication. Although plasma-assisted approaches have been long used in thin-film deposition and the top-down scheme of micro-/nanofabrication, fabrication of zero- and one-dimensional inorganic nanostructures through the bottom-up scheme is a relatively new focus of plasma application. In this article, recent plasma-assisted techniques in inorganic zero- and one-dimensional nanostructure fabrication are reviewed, which includes four categories of plasma-assisted approaches: plasma-enhanced chemical vapor deposition, thermal plasma sintering with liquid/solid feeding, thermal plasma evaporation and condensation, and plasma treatment of solids. The special effects and the advantages of plasmas on nanostructure fabrication are illustrated with examples, emphasizing on the understandings and ideas for controlling the growth, structure, and properties during plasma-assisted fabrications. This Review provides insight into the utilization of the special properties of plasmas in nanostructure fabrication.
Co-reporter:Jie Zheng;Rong Yang;Lei Xie;Jianglan Qu;Yang Liu
Advanced Materials 2010 Volume 22( Issue 13) pp:
Publication Date(Web):
DOI:10.1002/adma.201090041
Co-reporter:Jing Huang, Jin Xie, Kai Chen, Lihong Bu, Seulki Lee, Zhen Cheng, Xingguo Li and Xiaoyuan Chen
Chemical Communications 2010 vol. 46(Issue 36) pp:6684-6686
Publication Date(Web):23 Aug 2010
DOI:10.1039/C0CC01041C
We report in this Communication a facile, two-step surface modification strategy to achieve manganese oxide nanoparticles with prominent MRI T1 contrast. In a U87MG glioblastoma xenograft model, we confirmed that the particles can accumulate efficiently in tumor area to induce effective T1 signal alteration.
Co-reporter:Junzhi Yang, Jie Zheng, Xuanzhou Zhang, Yaoqi Li, Rong Yang, Qingrong Feng and Xingguo Li
Chemical Communications 2010 vol. 46(Issue 40) pp:7530-7532
Publication Date(Web):16 Sep 2010
DOI:10.1039/C0CC02745F
Massive superconducting MgB2 nanofibers are obtained for the first time from Mg(BH4)2. The technique optimizes reaction conditions to only 1 h at 460 °C and provides nanofibers which exhibited satisfying superconducting properties. The morphology transformation according to temperature changes and the special mechanism of precursor inductive synthesis are discussed.
Co-reporter:Rong Yang, Jing Huang, Wei Zhao, Wenzhong Lai, Xuanzhou Zhang, Jie Zheng, Xingguo Li
Journal of Power Sources 2010 Volume 195(Issue 19) pp:6811-6816
Publication Date(Web):1 October 2010
DOI:10.1016/j.jpowsour.2010.04.069
Hollow nanospheres of Sn–Sb–Cu alloy composites have been successfully synthesized via co-reduction of metal chlorides in aqueous alkaline solution without using any surfactants or solid templates. A bubble assisted growth mechanism is proposed to account for the formation of the hollow nanostructures. The concentration of the reactants kinetically controls the nucleation rate of the alloy nuclei, making for the formation of the hollow nanospheres. Compared with the alloy nanoparticles, the hollow spheres exhibit relatively high electrochemical capacity and good cyclic retention when used as anode materials for lithium-ion batteries. The bubble assisted synthesis method can be readily explored for fabricating hollow nanostructure of other alloy system for functional material applications.
Co-reporter:Jianglan Qu, Bo Sun, Jie Zheng, Rong Yang, Yuntao Wang, Xingguo Li
Journal of Power Sources 2010 Volume 195(Issue 4) pp:1190-1194
Publication Date(Web):15 February 2010
DOI:10.1016/j.jpowsour.2009.08.069
Pd–Mg–Pd thin films prepared by magnetron sputtering could absorb hydrogen entirely at room temperature and dehydrogenate completely and rapidly in ambient air. Our investigations of the structural, optical and electrical properties gave a detailed insight into the desorption mechanism. The overall activation energy and the hydrogen diffusion coefficient were deduced to be 48 kJ mol−1 and 8.0 × 10−15 cm2 s−1 based on optical and electrochemical measurements, respectively. The desorption process followed the nucleation and growth mechanism by modeling and simulating the resistance data. The small activation energy and remarkable diffusion kinetics highlighted the applicability as on-board hydrogen storage systems.
Co-reporter:R. Yang, J. Zheng, J. Huang, X.Z. Zhang, J.L. Qu, X.G. Li
Electrochemistry Communications 2010 Volume 12(Issue 6) pp:784-787
Publication Date(Web):June 2010
DOI:10.1016/j.elecom.2010.03.033
Vertically aligned Indium oxide (In2O3) nanoblades are successfully obtained through plasma enhanced chemical vapor deposition (PECVD) approach. By using plasma, the reaction between InCl3 and O2 was able to take place, yielding vertically aligned blade like nanostructure. The novel In2O3 nanostructures exhibit improved electrochemical properties when used as anode materials for lithium-ion batteries. The In2O3 electrode reveals reversible capacity of 580 mAh g−1 after 100 cycles, much higher than that of the In2O3 thin films. The result suggests that proper structural modification of In2O3 thin film may contribute to the improvement of electrochemical properties. The In2O3 electrodes with large reversible capacity and stable cycling performance may provide new insight of anode materials applied in thin film lithium-ion batteries.
Co-reporter:Rong Yang, Yingan Gu, Yaoqi Li, Jie Zheng, Xingguo Li
Acta Materialia 2010 Volume 58(Issue 3) pp:866-874
Publication Date(Web):February 2010
DOI:10.1016/j.actamat.2009.10.001
Flower-shaped SnO2 nanoplates were successfully synthesized via a simple hydrothermal treatment of a mixture of tin(II) dichloride dihydrate (SnCl2·2H2O) and sodium citrate (Na3C6H5O7·2H2O) in alkali solution. The obtained SnO2 nanoplates were less than 5 nm thick and self-assembled into flower-shaped nanostructures. The introduction of citrate was essential for the preparation of the SnO2 nanoplates. The nanoscale shape and self-assembled architecture of SnO2 nanoparticles were mainly controlled by the alkalinity of the solution. When the self-assembled SnO2 nanostructures were used as anode materials in Li-ion batteries, they exhibit a reversible capacity of 670 mA h g−1 after 30 cycles and an average capacity fading of 0.95% per cycle after the second cycle. The good electrochemical performance of the SnO2 sample prepared via the hydrothermal synthesis indicates the possibility of fabricating specific self-assembled three-dimensional nanostructures for Li-ion batteries.
Co-reporter:Jianglan Qu, Bo Sun, Yang Liu, Rong Yang, Yaoqi Li, Xingguo Li
International Journal of Hydrogen Energy 2010 Volume 35(Issue 15) pp:8331-8336
Publication Date(Web):August 2010
DOI:10.1016/j.ijhydene.2009.12.007
We prepared Mg-based thin films by magnetron sputtering and presented a comparative and systematic study in their structural, optical and electrical characteristics. We built a thin film model to investigate their hydrogen absorption and desorption kinetics in ambient air, as well as chemical and electrical switching behaviors by analyzing transmittance and resistance data. The remarkably enhanced kinetics was achieved by preparing the sandwich-like structured film. The Pd–Mg–Pd film was found to exhibit better gasochromic, chemochromic and electrochromic properties, which could be attributed to the enhanced cooperation effect and more extended Mg–Pd interfaces. The structural effect of kinetics in thin films shed light on how to further improve the hydrogen storage performance in bulk Mg-based materials.
Co-reporter:Tong Liu, Yarong Zhu, Xuanzhou Zhang, Tongwen Zhang, Tao Zhang, Xingguo Li
Materials Letters 2010 Volume 64(Issue 23) pp:2575-2577
Publication Date(Web):15 December 2010
DOI:10.1016/j.matlet.2010.08.050
Ca(OH)2 nanoparticles have been synthesized with high purity and yield using the hydrogen plasma-metal reaction method. They are spherical in shape with a mean particle size of approximately 100 nm. The morphology of nanoparticles is spongy with mesopores, mostly less than 10 nm. The pore volume and surface area of Ca(OH)2 nanoparticles are 0.084 cm3/g and 28.7 m2/g, respectively. Both transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis demonstrated that these nanoparticles possess poly-nanocrystalline structure with an average grain size of about 10 nm. The formation mechanism of Ca(OH)2 nanoparticles was discussed in terms of chemical reactions and coalescence during the processing.
Co-reporter:Rong Yang ; Wei Zhao ; Jie Zheng ; Xuanzhou Zhang
The Journal of Physical Chemistry C 2010 Volume 114(Issue 47) pp:20272-20276
Publication Date(Web):November 9, 2010
DOI:10.1021/jp107396a
Carbon-coated SnO2 nanoparticles were synthesized by a simple one-pot hydrothermal treatment. During the hydrothermal process, SnO2 was formed by the hydrolysis of tin(II) dichloride dihydrate (SnCl2·2H2O) in alkali solution, while sucrose was used as the carbon source to form the coated polysaccharide shell on the SnO2 nanoparticles. In the obtained carbon-coated SnO2 nanoparticles, SnO2 nanocrystals with a diameter of 4 nm were observed to be homogeneously dispersed in the particles. After calcination, the product exhibited improved lithium storage properties, as compared to pure SnO2 nanoparticles. The carbon-coated SnO2 nanoparticles exhibit 430 mAh g−1 reversible capacities after 100 cycles and an average capacity fading of 0.2% per cycle after the 20th cycle. The good electrochemical performances of the carbon-coated SnO2 nanoparticles indicate that the obtained carbon shell can effectively increase the stability of the active materials and improve the cycling performance of oxide-based anode materials for lithium-ion batteries.
Co-reporter:Dr. Yaoqi Li;Dr. Ping Song; Jie Zheng ; Xingguo Li
Chemistry - A European Journal 2010 Volume 16( Issue 35) pp:10887-10892
Publication Date(Web):
DOI:10.1002/chem.201000391
Abstract
The application of ammonium borane (AB) as a hydrogen storage material is limited by the sluggish kinetics of H2 release. Two catalysts based on metal–organic frameworks (MOFs) have been prepared either by applying MOF as precursors or by the in situ reduction method. In the release of H2 from AB, the high H2 content of the whole system, the remarkably lower reaction onset temperature, the significantly increased H2 release rates at ≤90 °C, and the decreased reaction exothermicity have all been achieved with only 1.0 mol % MOF-based catalyst. Moreover, the clear catalytic diversity of three catalysts has been observed and discussed. The in situ synthesized Ni0 sites and the MOF supports in the catalysts were proven to show significant and different effects to promote the catalytic activities. With MOF-based catalysts, both the enhanced kinetics and the high H2 capacity of the AB system present great advantages for future use.
Co-reporter:Jing Huang, Lihong Bu, Jin Xie, Kai Chen, Zhen Cheng, Xingguo Li, and Xiaoyuan Chen
ACS Nano 2010 Volume 4(Issue 12) pp:7151
Publication Date(Web):November 2, 2010
DOI:10.1021/nn101643u
The effect of nanoparticle size (30−120 nm) on magnetic resonance imaging (MRI) of hepatic lesions in vivo has been systematically examined using polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles (PVP-IOs). Such biocompatible PVP-IOs with different sizes were synthesized by a simple one-pot pyrolysis method. These PVP-IOs exhibited good crystallinity and high T2 relaxivities, and the relaxivity increased with the size of the magnetic nanoparticles. It was found that cellular uptake changed with both size and surface physiochemical properties, and that PVP-IO-37 with a core size of 37 nm and hydrodynamic particle size of 100 nm exhibited higher cellular uptake rate and greater distribution than other PVP-IOs and Feridex. We systematically investigated the effect of nanoparticle size on MRI of normal liver and hepatic lesions in vivo. The physical and chemical properties of the nanoparticles influenced their pharmacokinetic behavior, which ultimately determined their ability to accumulate in the liver. The contrast enhancement of PVP-IOs within the liver was highly dependent on the overall size of the nanoparticles, and the 100 nm PVP-IO-37 nanoparticles exhibited the greatest enhancement. These results will have implications in designing engineered nanoparticles that are optimized as MR contrast agents or for use in therapeutics.Keywords: iron oxide; magnetic nanoparticles; magnetic resonance imaging; size dependent
Co-reporter:Jianglan Qu, Yuntao Wang, Lei Xie, Jie Zheng, Yang Liu, Xingguo Li
Journal of Power Sources 2009 Volume 186(Issue 2) pp:515-520
Publication Date(Web):15 January 2009
DOI:10.1016/j.jpowsour.2008.10.079
Pd-capped Mg films prepared by magnetron sputtering achieved complete dehydrogenation in air at room temperature and behaved as favorable gasochromic switchable mirrors. Their cyclic hydrogen absorption and desorption kinetics in air were investigated by using the Bruggeman effective medium approximation. The overall activation energy was 80 kJ mol−1, while the reaction orders controlling desorption were deduced to be n = 2 at 328 K and n = 1 at lower temperatures by analyzing the transmittance data. The hydrogen diffusion coefficient and the corresponding activation energy were calculated by electrochemical measurements. Mg thin films exhibited the smaller activation energy and remarkable diffusion kinetics at room temperature which implied potential applications in smart windows.
Co-reporter:Jianglan Qu, Yuntao Wang, Lei Xie, Jie Zheng, Yang Liu, Xingguo Li
International Journal of Hydrogen Energy 2009 Volume 34(Issue 4) pp:1910-1915
Publication Date(Web):February 2009
DOI:10.1016/j.ijhydene.2008.12.039
We prepared Pd-capped Mg thin films by direct current (DC) magnetron sputtering. We investigated their structural, optical and electrical properties, as well as the effect of annealing on these films during hydrogenation and dehydrogenation. The hydrogen absorption behaviors at both room temperature and 353 K, and dehydrogenation at 353 K, were studied. The Mg film annealed at 473 K for 2 h exhibited the best absorption kinetics and superior switchable mirror properties among all the samples annealed at different temperatures. We concluded that annealing temperature is a crucial parameter in forming high-quality Mg films. The improved hydriding kinetics can be attributed to the favorable morphology and structure induced by the annealing process.
Co-reporter:Lei Xie, Yang Liu, Xuanzhou Zhang, Jianglan Qu, Yuntao Wang, Xingguo Li
Journal of Alloys and Compounds 2009 Volume 482(1–2) pp:388-392
Publication Date(Web):12 August 2009
DOI:10.1016/j.jallcom.2009.04.028
Mg and Ni nanoparticles were prepared by hydrogen plasma-metal reaction (HPMR). MgH2 nanoparticles were obtained by hydriding the Mg nanoparticles. Hydrogen storage kinetics of the MgH2 nanoparticles doped with different amount of Ni nanoparticles was investigated by differential scanning calorimetry (DSC) and hydrogen desorption rate measurements. The obtained samples show superior hydrogen storage kinetics. 6.1 wt% hydrogen is desorbed in 10 min at 523 K under an initial pressure of 0.01 bar of H2 when the proportion of Ni nanoparticles is 10 wt%. The desorption rate increases when enhancing the amount of catalyst. However, the activation energy of desorption does not decrease any more when the amount of Ni exceeds a value. The enhanced desorption kinetics are mainly attributed to the accelerated combination process of hydrogen atoms by the Ni nanoparticles on the surface of MgH2.
Co-reporter:Lei Xie, Yang Liu, Guanqiao Li and Xingguo Li
The Journal of Physical Chemistry C 2009 Volume 113(Issue 32) pp:14523-14527
Publication Date(Web):July 21, 2009
DOI:10.1021/jp904346x
Mg(NH2)2 with three different particle sizes of 100, 500, and 2000 nm are obtained by a series of reactions between Mg, H2, and NH3. The ammonia desorption temperature decreases with the particle size. In addition, the hydrogen desorption kinetics increases obviously with decreasing the particle size of amide after mixing with LiH. The desorption activation energy of the three mixed samples is 122.2, 134.7, and 182.0 kJ/mol with increasing the particle size. After dehydrogenation, the particle size of the product is similar to that of the amide before dehydrogenation. Due to the larger specific surface area and reduced diffusion distance, the absorption kinetics increases as well with decreasing the particle size. The relationship between particle size and hydrogen sorption kinetics is also discussed.
Co-reporter:Jing Huang, Weimeng Chen, Wei Zhao, Yaoqi Li, Xingguo Li and Chinping Chen
The Journal of Physical Chemistry C 2009 Volume 113(Issue 28) pp:12067-12071
Publication Date(Web):June 22, 2009
DOI:10.1021/jp810662j
One-dimensional (1D) chainlike arrays of hollow magnetic Fe3O4 spheres have been prepared by simply aging magnetically preassembled Fe nanoparticles in aqueous solution at room temperature. The diameter of the 1D nanomaterials is about 100−200 nm, and the length is up to 1−3 μm, observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The structure and magnetic properties of the Fe3O4 hollow chains were characterized by X-ray powder diffraction (XRD) and via a superconducting quantum interference device (SQUID) magnetometer. Mechanism investigations on the time dependent process reveal these hollow nanostructures were formed based on the nanoscale Kirkendall effect. Besides the aqueous microenvironment, the partial pressure of oxygen is of great importance in the formation of 1D chainlike Fe3O4 hollow nanostructures.
Co-reporter:Yaoqi Li Dr.;Lei Xie Dr.;Yan Li Dr.;Jie Zheng Dr. Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 36) pp:8951-8954
Publication Date(Web):
DOI:10.1002/chem.200901465
Co-reporter:Yonghua Leng;Jie Zheng;Jianglan Qu
Journal of Materials Science 2009 Volume 44( Issue 17) pp:4599-4603
Publication Date(Web):2009 September
DOI:10.1007/s10853-009-3701-7
The thermal stability and magnetic anisotropies of nickel nanoplates with {111} planes as the exposure plane are studied. The melting point of Ni nanoplates drastically drops as compared to that of the bulk one due to the significant increase in the surface free energy. For the large aspect ratio, these nanoplates tend to lie flat on silicon wafer and form a thin Ni {111} plane film. Both the coercivity and the remnant magnetization of the Ni film deeply depend on the applied field direction. As the angle between the film plane and the applied field direction varies from zero to 45° and to 90°, the coercivity measured at 5 K increases from 335 Oe to 373 and to 410 Oe. Correspondingly, the remnant magnetization decreases from 18.1 to 15.8 to be 10.4 emu/g.
Co-reporter:Yang Liu, Lei Xie, Yan Li, Rong Yang, Jianglan Qu, Yaoqi Li, Xingguo Li
Journal of Power Sources 2008 Volume 183(Issue 2) pp:701-707
Publication Date(Web):1 September 2008
DOI:10.1016/j.jpowsour.2008.05.057
Cubic SrTiO3 powders were synthesized by three methods: the polymerized complex (PC) method, the solid state reaction, and the milling assistant method. The samples obtained were characterized by X-ray diffraction (XRD), UV–vis spectroscopy (UV–vis), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The mean diameters of the as-synthesized SrTiO3 particles were 30 nm by the polymerized complex method, 140 nm by the solid state reaction, and 30 nm by the milling assistant method. The photocatalytic activity of hydrogen evolution from water splitting over SrTiO3 powders by the polymerized complex method is higher than that by the solid state reaction and the milling assistant method. Particle size, uniformity of components, and particle aggregation extent affect the photocatalytic activity of SrTiO3 for hydrogen evolution. The best rate of photocatalytic hydrogen evolution over SrTiO3 by the polymerized complex method under UV illumination is as high as 3.2 mmol h−1 g−1.
Co-reporter:Yaoqi Li ; Lei Xie ; Yang Liu ; Rong Yang
Inorganic Chemistry 2008 Volume 47(Issue 22) pp:10372-10377
Publication Date(Web):October 15, 2008
DOI:10.1021/ic800919k
Two metal−organic frameworks of M(HBTC)(4,4′-bipy)·3DMF (M = Ni and Co; H3BTC = 1,3,5-benzenetricarboxylic acid; 4,4′-bipy = 4,4′-bipyridine; DMF = N,N′-dimethylformamide) were synthesized by a one-pot solution reaction and a solvothermal method, respectively. The as-prepared samples have high specific surface areas of 1590 m2/g and 887 m2/g. The activation at different temperatures for the guest removal prior to gas loading obviously affects the gas sorption process. Ni(HBTC)(4,4′-bipy)·3DMF shows high hydrogen storage capacities of 1.20 wt % at room temperature and 3.42 wt % at 77 K. Co(HBTC)(4,4′-bipy)·3DMF shows capacities of 0.96 wt % at 298 K and 2.05 wt % at 77 K. The hydrogen adsorption heats in the two compounds decrease slightly as a function of the amount adsorbed, and it confirms that the H2 molecules are combined with stronger sites preferentially. Research on the kinetics of hydrogen adsorption shows a fast saturation process (80 s) and no obvious capacity loss after 20 cycles.
Co-reporter:Jie Zheng, Xubo Song, Nan Chen and Xingguo Li
Crystal Growth & Design 2008 Volume 8(Issue 5) pp:1760
Publication Date(Web):April 10, 2008
DOI:10.1021/cg700804t
In this paper, we report a new scheme for chemical vapor deposition (CVD) of CdS nanocrystals, in which polysulfide and cadmium chloride were used as the sulfur and cadmium source, respectively. During the reaction, hydrogen sulfide was generated by controlled hydrolysis of polysulfide and reacted with cadmium chloride to give CdS. Tetrahedral CdS nanocrystals with homogeneous size and nearly perfect Td point group symmetry were obtained in high yield. The source and deposition temperature were only 540 and 400 °C, respectively, which were significantly lower than those in conventional CVD methods. The low deposition temperature was found critical for the formation of the tetrahedral nanostructures. The photoluminescence spectra of the tetrahedral nanocrystals consisted of a sharp band edge emission peak and a broad band related to trapped states.
Co-reporter:Yuntao Wang, Wei Hua, Jianglan Qu, Lei Xie, Xingguo Li
International Journal of Hydrogen Energy 2008 Volume 33(Issue 23) pp:7207-7213
Publication Date(Web):December 2008
DOI:10.1016/j.ijhydene.2008.06.022
A multilayer film of Mg and Ni was prepared by dc/ac magnetron sputtering and annealed below 623 K in vacuum to obtain polycrystalline Mg2Ni thin films. The phase transformation during heating process and optical switching properties of the films were investigated. The influence of the original crystalline state of Mg2Ni films on optical switching properties such as transmission, optical band gaps and the cycle times was discussed. The indirect optical band gaps of the fully hydrogenated amorphous Mg2Ni films were estimated by linear extrapolation.
Co-reporter:Yonghua Leng, Lei Xie, Fuhui Liao, Jie Zheng, Xingguo Li
Thermochimica Acta 2008 Volume 473(1–2) pp:14-18
Publication Date(Web):10 July 2008
DOI:10.1016/j.tca.2008.04.003
The thermal decompositions (including TG and DSC) of nickel carbide were studied under different atmospheres of Ar, air and H2. X-ray diffraction combined with element analysis indicated that nickel metal, together with solid amorphous carbon, was formed during Ni3C decomposition in Ar atmosphere, accompanying mass invariant in this process. While in H2 atmosphere nickel metal was the only residual from reactions. The carbon component of nickel carbide reacted with H2 to form methane as the main volatile gases. Both the nickel and carbon components of Ni3C reacted with O2 in the air to form their corresponding oxides. Moreover, we calculated the activation energy for the decomposition process and the molar enthalpy of formation of Ni3C based on the thermal analysis.
Co-reporter:Jie Zheng, Yuan Yang, Bo Yu, Xubo Song and Xingguo Li
ACS Nano 2008 Volume 2(Issue 1) pp:134
Publication Date(Web):January 5, 2008
DOI:10.1021/nn700363t
This paper presents a systematic investigation on the controlled synthesis of wurtzite aluminum nitride (AlN) one-dimensional (1D) nanostructures in a chemical vapor deposition (CVD) system using Al and NH3 as starting materials. By controlling reaction temperature and NH3 flow, nanostructures with manifold morphologies including nanoneedles, branched nanoneedles, short nanorods, slim nanorods, and nanofences were synthesized with high yield and selectivity. The correlation between experiment parameters and product morphologies was interpreted by a surface diffusion based model. Moreover, electrical properties of a single nanoneedle were studied for the first time, in which typical semiconductor characteristics were observed. Silicon was speculated to incorporate into the AlN nanoneedle from silicon substrates during the synthesis, which served as an n-type donor and was responsible for the observed electrical behavior. Keywords: Aluminum nitride; controlled synthesis; electrical properties; one-dimensional nanostructures
Co-reporter:Jie Zheng, Bo Sun, Rong Yang, Xubo Song, Xingguo Li and Yikang Pu
The Journal of Physical Chemistry B 2008 Volume 112(Issue 40) pp:12748-12752
Publication Date(Web):September 12, 2008
DOI:10.1021/jp8035204
In this paper we reported that low temperature plasma may reverse the direction of a chemical reaction. The thermodynamically forbidden reaction between H2 and AlCl3 was able to take place with the assistance of low temperature plasma, yielding metal Al. The plasma chemistry of the reaction was investigated by optical emission spectroscopy, which suggested that the dissociation of H2 and AlCl3 molecules by plasma led the reaction to a thermodynamically favorable one by creating reaction channels with low Gibbs free energy change. The addition of Ar promoted the reaction kinetics dramatically, which was attributed to the enhanced dissociation of AlCl3 molecules by excited Ar species.
Co-reporter:L. Xie, Y. Liu, Y.T. Wang, J. Zheng, X.G. Li
Acta Materialia 2007 Volume 55(Issue 13) pp:4585-4591
Publication Date(Web):August 2007
DOI:10.1016/j.actamat.2007.04.020
Abstract
MgH2 nanoparticles were obtained by hydriding ultrafine magnesium particles which were prepared by hydrogen plasma–metal reaction. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the obtained sample is almost pure MgH2 phase, without residual magnesium and with an average particle size of ∼300 nm. Milled with 5 wt.% TiF3 as a doping precursor in a hydrogen atmosphere, the sample desorbed 4.5 wt.% hydrogen in 6 min under an initial hydrogen pressure of ∼0.001 bar at 573 K and absorbed 4.2 wt.% hydrogen in 1 min under ∼20 bar hydrogen at room temperature. Compared with MgH2 micrometer particles doped with 5 wt.% TiF3 under the same conditions as the MgH2 nanoparticles, it is suggested that decrease of particle size is beneficial for enhancing absorption capacity at low temperatures, but has no effect on desorption. In addition, the catalyst was mainly responsible for improving the sorption kinetics and its catalytic mechanism is discussed.
Co-reporter:Zhong Wang, Wenhuai Tian, Xingguo Li
Journal of Alloys and Compounds 2007 Volume 439(1–2) pp:350-354
Publication Date(Web):31 July 2007
DOI:10.1016/j.jallcom.2006.08.247
Ultrafine particles of Sn–Sb alloys with different chemical composition have been prepared by hydrogen plasma-metal reaction. Structure, morphology, size and chemical composition of the Sn–Sb ultrafine particles were investigated by transmission electron microscopy, X-ray diffraction, BET gas adsorption, and induction-coupled plasma spectroscopy. It was found that all the particles have spherical shapes, with average particle size in the range of 100–300 nm. The electrochemistry properties as an alternative anode material for lithium-ion batteries have been characterized by constant current cycling and cyclic voltammetry. Electrochemical measurements showed that the alloys with Sn–46.5 at.% Sb have best reversible capacity and capacity retention. It exhibited a high reversible lithium-ion storage capacity of 701 mAh g−1 in the initial cycle, which has remained at 81% (i.e., 566 mAh g−1) of its original capacity after 20 cycles.
Co-reporter:Yan Li, Yang Liu, Yuntao Wang, Yonghua Leng, Lei Xie, Xingguo Li
International Journal of Hydrogen Energy 2007 Volume 32(Issue 15) pp:3411-3415
Publication Date(Web):October 2007
DOI:10.1016/j.ijhydene.2007.03.006
[M(Py){Ni(CN)4}](M=Fe,Co,Ni) frameworks were synthesized by solution method and their hydrogen storage properties were measured using a PCT measuring system. The series of frameworks were found to adsorb twice hydrogen predicted by monolayer adsorption model. Compared with the hydrogen adsorption property of FeFe(CN)6, this strange phenomenon is elucidated at a molecular level. The pore diameter of Py series is just enough to contain two hydrogen molecules but only one nitrogen molecule is permitted to get in, which leads to the apparent double-layer adsorption. It is concluded that pores with free diameter smaller than 0.42 nm are not favorable for hydrogen storage because no more than one hydrogen molecule can get into them.
Co-reporter:Yan Li, Donglin Zhao, Yuntao Wang, Risheng Xue, Zengmin Shen, Xingguo Li
International Journal of Hydrogen Energy 2007 Volume 32(Issue 13) pp:2513-2517
Publication Date(Web):September 2007
DOI:10.1016/j.ijhydene.2006.11.010
Carbon materials were obtained by the thermal decomposition of organic reagents, and different surface states are achieved by treatment in different conditions. SEM, XRD and BET were used to characterize the samples. Hydrogen storage of the samples was measured at liquid nitrogen temperature. Combining these results and others’ work, a mechanism for hydrogen storage in carbon materials is proposed that hydrogen is stored at different sites with different mechanisms. With this hypothesis, the hydrogen storage properties of carbon materials can be forecasted quantitatively.
Co-reporter:L. Xie, H.Y. Shao, Y.T. Wang, Y. Li, X.G. Li
International Journal of Hydrogen Energy 2007 Volume 32(Issue 12) pp:1949-1953
Publication Date(Web):August 2007
DOI:10.1016/j.ijhydene.2006.09.044
The homogeneous Mg2Ni1-xCoxMg2Ni1-xCox (x=0.05x=0.05, 0.1) compounds were successfully prepared from magnesium, nickel and cobalt ultrafine particles, which were obtained from a hydrogen plasma–metal reaction. XRD and TEM results demonstrate that the homogeneous nanostructured Mg2Ni1-xCoxMg2Ni1-xCox with less impurity were successfully synthesized by this method. DSC in hydrogen atmosphere, pressure–composition isotherm and the kinetics of hydrogen adsorption/desorption were investigated. The results show that the nanostructured Mg2Ni1-xCoxMg2Ni1-xCox compounds present superior sorption kinetics.
Co-reporter:Jie Zheng, Xubo Song, Yaohua Zhang, Yan Li, Xingguo Li, Yikang Pu
Journal of Solid State Chemistry 2007 Volume 180(Issue 1) pp:276-283
Publication Date(Web):January 2007
DOI:10.1016/j.jssc.2006.10.011
Nanosized aluminum nitride hollow spheres were synthesized by simply heating aluminum nanoparticles in ammonia at 1000 °C. The as-synthesized sphere shells are polycrystalline with cavity diameters ranging from 15 to 100 nm and shell thickness from 5 to 15 nm. The formation mechanism can be explained by the nanoscale Kirkendall effect, which results from the difference in diffusion rates between aluminum and nitrogen. The Al nanoparticles served as both reactant and templates for the hollow sphere formation. The effects of precursor particle size and temperature were also investigated in terms of product morphology. Room temperature cathode luminescence spectrum of the nanosized hollow spheres showed a broad emission band centered at 415 nm, which is originated from oxygen related luminescence centers. The hollow structure survived a 4-h heat treatment at 1200 °C, exhibiting excellent thermal stability.Nanosized aluminum nitride hollow spheres were synthesized by nitridation of aluminum nanoparticles at 1000 °C using ammonia.
Co-reporter:Xubo Song, Yaohua Zhang, Jie Zheng, Xingguo Li
Journal of Physics and Chemistry of Solids 2007 Volume 68(Issue 9) pp:1681-1684
Publication Date(Web):September 2007
DOI:10.1016/j.jpcs.2007.04.011
Wurtzite ZnO nanonails on silicon substrate were successfully synthesized by thermal vapor transport and condensation method at a low temperature without a metal catalyst. Pure Zn powders were used as raw material and O2/Ar powders as source gas. The products were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that the deposited nanostructures include aligned ZnO nanonails. The ZnO nanonails, with crystalline cap and small-diameter shafts, grow along the c-axis. The optical properties have been revealed by photoluminescence spectra. We considered that the ZnO nanonails growth is a vapor–solid process.
Co-reporter:Xingguo Li, Tong Liu, Masaya Sato, Seiki Takahashi
Powder Technology 2006 Volume 163(Issue 3) pp:183-187
Publication Date(Web):28 April 2006
DOI:10.1016/j.powtec.2006.02.003
The plasma state and nanoparticle formation of Ti–Fe alloys were studied by nitrogen plasma metal reaction. The nitrogen plasma state is dependent on the nitrogen partial pressure and the master alloy composition. Synthesis of Ti–Fe nanoparticles can be carried out only when the nitrogen partial pressure is smaller than 10% or the Ti composition is larger than 50 at.%. The as-received nanoparticles are composed of TiN and Fe phases with the mean particle diameters ranging from 25 to 40 nm; the TiN and Fe nanoparticles have quadrangular and spherical appearance, respectively. The nitrogen plasma promotes Fe evaporation more strongly than Ti, and as a result the as-received nanoparticles are Fe-rich. Compared with the hydrogen plasma, the nitrogen plasma has a smaller effect on evaporation enhancement, but stronger reactivity.
Co-reporter:Zhong Wang, A.L. Fan, W.H. Tian, Y.T. Wang, X.G. Li
Materials Letters 2006 Volume 60(17–18) pp:2227-2231
Publication Date(Web):August 2006
DOI:10.1016/j.matlet.2005.12.116
Eight kinds of Ni–Al nanoparticles have been prepared by hydrogen plasma–metal reaction. The morphology, crystal structure and chemical composition of the nanoparticles obtained in this study were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and induction-coupled plasma (ICP) spectroscopy. The particle size was determined by TEM and BET gas adsorption. It was found that all the nanoparticles have spherical shapes, with average particle size in the range of 14∼62 nm. The crystal structures of Ni–Al nanoparticles vary with the composition of master alloys. Pure Al3Ni2 (D513), NiAl (B2) and Ni3Al (L12) structures were successfully produced with 55.0, 58.3 and 72.6 at.% Ni in bulk, respectively. The analysis result about the phase equilibrium based on the crystal structures of nanoparticles is not consistent with those based on the equilibrium phase diagram.
Co-reporter:Z. Wang, W.H. Tian, X.H. Liu, Y. Li, X.G. Li
Materials Chemistry and Physics 2006 Volume 100(Issue 1) pp:92-97
Publication Date(Web):10 November 2006
DOI:10.1016/j.matchemphys.2005.12.011
Four kinds of Si–Ni nanoparticles were prepared by hydrogen plasma–metal reaction as anode materials of a lithium-ion cell. The morphology and crystal structure of nanoparticles were investigated by transmission electron microscopy (TEM), and X-ray diffraction (XRD). The electrochemistry properties were studied as the anode for lithium-ion batteries. During lithium insertion into the alloy electrodes, Si act as active centre, which reacts with Li to form amorphous LixSi alloys, while the Si2Ni in the sample plays the role of matrix as an inertial phase, which can buffer silicon volume expansion and facilitate charge transfer among silicon particles. Electrochemical measurements show that the charge-discharge capacity of Si–Ni alloys increases with decreasing Si2Ni. A high lithium storage capacity of 1304 mAh g−1 is observed for the Si–Ni alloy at Ni 9.0 at.% in nanoparticles with some reversibility.
Co-reporter:Huaiyu Shao, Yuntao Wang, Hairuo Xu, Xingguo Li
Journal of Solid State Chemistry 2005 Volume 178(Issue 7) pp:2211-2217
Publication Date(Web):July 2005
DOI:10.1016/j.jssc.2005.04.036
We successfully synthesized Mg2Cu alloys from the metal nanoparticles, which are produced from hydrogen plasma-metal reaction method, in two ways. One is under 0.1 MPa argon at 673 K and the other is under 4.0 MPa hydrogen at 673 K. The structure, morphology and reaction mechanism were studied. The hydrogen absorption and the pressure-composition isotherm properties of the obtained Mg2Cu alloy under hydrogen were studied. The van’t Hoff equation and the formation enthalpy and entropy of the resulting hydride (MgH2+MgCu2) were obtained from the equilibrium plateau pressures of the desorption isotherms. Nanostructured Mg2Cu shows excellent hydrogen storage properties because nanostructured materials have more surface area and more defects, which means more nucleation sites with hydrogen, and smaller particles, which means shorter diffusion distance for hydrogen in the alloys particles.Nanostructured Mg2Cu alloys were synthesized from Mg and Cu nanoparticles and the hydrogen storage behavior of the Mg–Cu–H system was studied.
Co-reporter:Li Li, Li Guoling, Xu Li, Xiong Yifu, Li Xingguo
Rare Metal Materials and Engineering (October 2016) Volume 45(Issue 10) pp:
Publication Date(Web):1 October 2016
DOI:10.1016/S1875-5372(17)30024-3
“Oxygen-free” Gd was fabricated by hydrogen plasma arc melting (HPAM). The HPAM is more different than the traditional Ar plasma arc melting (PAM) in Oxygen removal. It is attributable to the hydrogen atoms dissociated and activated in high temperature HPAM. In addition an increased diffusion of oxygen in Gd-O solid solution to the surface also plays an important role in removal of oxygen. The substances are confirmed by optical emission spectroscopy (OES), which are involved in the plasma like Ar I, Ar II and H I and some possible reactions. The effect of H with thermodynamic estimation was discussed in detail.
Co-reporter:Yanyan Wang, Gongbiao Xin, Chongyun Wang, Huiyu Li, ... Xingguo Li
Journal of Energy Chemistry (May 2014) Volume 23(Issue 3) pp:287-290
Publication Date(Web):1 May 2014
DOI:10.1016/S2095-4956(14)60149-2
Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated. It is found that rising substrate temperature to 60 °C can coarsen the surface of thin film, thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to ~1725 mAh·g−1. Simultaneously, the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature. In addition, the specimen exhibits a very long and flat discharge plateau at about −0.67 V, at which nearly 60% of capacity is maintained. The property is favorable for the application in metal hydride/nickel secondary batteries. The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.Rising optimal substrate temperature has a beneficial effect on the discharge capacity and cyclic stability of Mg78Y22 thin films.Download full-size image
Co-reporter:Junzhi Yang, Jie Zheng, Xuanzhou Zhang, Yaoqi Li, Rong Yang, Qingrong Feng and Xingguo Li
Chemical Communications 2010 - vol. 46(Issue 40) pp:NaN7532-7532
Publication Date(Web):2010/09/16
DOI:10.1039/C0CC02745F
Massive superconducting MgB2 nanofibers are obtained for the first time from Mg(BH4)2. The technique optimizes reaction conditions to only 1 h at 460 °C and provides nanofibers which exhibited satisfying superconducting properties. The morphology transformation according to temperature changes and the special mechanism of precursor inductive synthesis are discussed.
Co-reporter:Tong Liu, Yurong Cao, Gongbiao Xin and Xingguo Li
Dalton Transactions 2013 - vol. 42(Issue 37) pp:NaN13697-13697
Publication Date(Web):2013/07/05
DOI:10.1039/C3DT51628H
The MgxNi100−x films of 100 nm have been prepared by magnetron co-sputtering Mg and Ni targets, and a Pd layer of 10 nm was deposited on these films by magnetron sputtering a Pd target. Mg2Ni and MgNi2 are directly generated during the co-sputtering process in the Mg84Ni16/Pd and Mg48Ni52/Pd films. The hydrogen storage properties of the films under 0.1 MPa H2 at 298 K were investigated. The hydrogenation of the Mg84Ni16/Pd film saturates within 45 s and exhibits the faster absorption kinetics compared with Mg94Ni6/Pd and Mg48Ni52/Pd films. The electrochemical properties of the MgxNi100−x/Pd films were investigated in 6 M KOH with a three-electrode cell. The Mg84Ni16/Pd film can be activated just at the first cycle. The maximum discharge capacity of the Mg84Ni16/Pd film is 482.7 mAh g−1, the highest among these films.
Co-reporter:Gongbiao Xin, Yanyan Wang, He Fu, Guoling Li, Jie Zheng and Xingguo Li
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 7) pp:NaN3006-3006
Publication Date(Web):2013/12/09
DOI:10.1039/C3CP54714K
In this paper, the structures of 500 nm thick Mg–Pd films were tailored by insertion of 1 nm thin Ti interlayers, and their electrochemical hydrogen storage properties were investigated. Results showed that thin Ti interlayers in the Mg bulk film could significantly improve the discharge properties of thick Mg–Pd films. The Mg100–Ti1 sample exhibited the most promising electrochemical properties, including a shorter activation period, larger discharge capacity, superior cyclic stability and high rate discharge capability, due to the creation of numerous interfaces and nucleation sites, reduction of the hydrogen diffusion path, and synergetic catalytic effects of Pd and Ti layers.
Co-reporter:Wei Wang, Chongyun Wang, Wei Li, Xinxin Fan, Zhonghua Wu, Jie Zheng and Xingguo Li
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 34) pp:NaN14395-14395
Publication Date(Web):2013/06/21
DOI:10.1039/C3CP51875B
Silica microcapsules with hierarchical pore structure are prepared using a one step emulsion templated hydrolysis method. Silica particles of around 100 nm with percolated nanosized pores are self-assembled into micrometer scale spherical shells. The porous structure serves as an ideal host for shape stabilization of melted organic compounds. Small angle X-ray scattering (SAXS) results show that the n-eicosane encapsulated in nanoporous silica consists of mass fractal structure with a fractal dimension of 2.1. n-Eicosane encapsulated in the nanosized pores exhibits novel phase change behavior. A large melting point drop from 37.0 to 28.8 °C is observed, which is attributed to the strong interaction between the n-eicosane molecules and the silica skeleton.
Co-reporter:Yong Wu, Xiaojing Jiang, Jun Chen, Yue Qi, Yuxuan Zhang, He Fu, Jie Zheng and Xingguo Li
Dalton Transactions 2017 - vol. 46(Issue 14) pp:NaN4503-4503
Publication Date(Web):2017/03/06
DOI:10.1039/C7DT00337D
Boric acid effectively promotes the dehydrogenation of lithium borohydride due to the interactions between protonic and hydridic hydrogen. The simple mixture of LiBH4–(4/3)B(OH)3 can release 5.6 wt% hydrogen below 180 °C with only a trace amount of water, thus constituting a highly attractive single-use hydrogen storage material.
Co-reporter:Zhiliang Liu, Xinghua Chang, Bingxue Sun, Sungjin Yang, Jie Zheng and Xingguo Li
Chemical Communications 2017 - vol. 53(Issue 46) pp:NaN6226-6226
Publication Date(Web):2017/05/15
DOI:10.1039/C7CC02857A
SiCl4 can be directly reduced to nano-Si with commercial Na metal under solvent-free conditions by mechanical milling. Crystalline nano-Si with an average size of 25 nm and quite uniform size distribution can be obtained, which shows excellent lithium storage performance, for a high reversible capacity of 1600 mA h g−1 after 500 cycles at 2.1 A g−1.
Co-reporter:Jun Chen, Jun Fu, Kai Fu, Rui Xiao, Yong Wu, Xinyao Zheng, Zhiliang Liu, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2017 - vol. 5(Issue 27) pp:NaN14318-14318
Publication Date(Web):2017/06/13
DOI:10.1039/C7TA01954H
The hydrogen evolution reaction (HER) during the electrochemical oxidation of borohydride is the major efficiency loss in direct borohydride fuel cells (DBFCs). Here we show that an YH2–Pd thin film electrode, which combines catalysis on the Pd layer and H storage in the YH2 layer, can effectively promote the energy utilization efficiency. The YH2 layer can absorb the atomic H generated during the BH4− oxidation on the Pd layer and effectively suppress HER. The absorbed H can be further oxidized into H2O in NaOH solution, allowing full utilization of the 8 electrons in BH4− oxidation. The YH2–Pd electrode can be regarded as a hybridization of the anodes in conventional DBFCs and nickel-metal hydride batteries. The hydrogen absorption/desorption during the electrochemical process is in situ monitored by optical transmittance measurements, which provide key insights into the interconversion mechanisms and energetics of the hydridic, neutral and protonic hydrogen species.
Co-reporter:Chongyun Wang, Lili Feng, Huazhe Yang, Gongbiao Xin, Wei Li, Jie Zheng, Wenhuai Tian and Xingguo Li
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 38) pp:NaN13238-13238
Publication Date(Web):2012/08/06
DOI:10.1039/C2CP41988B
Graphene oxide (GO) sheets were introduced to stabilize the melted polyethylene glycol (PEG) during the solid–liquid phase change process, which can be used as a smart heat storage system. The structural properties and phase change behaviors of the PEG–GO composites were comprehensively investigated as a function of the PEG content by means of various characterization techniques. The highest stabilized PEG content is 90 wt% in the composites, resulting in a heat storage capacity of 156.9 J g−1, 93.9% of the phase change enthalpy of pure PEG. Notably, GO has much stronger impact on lowering of the phase change temperature of PEG compared with some other porous carbon materials (activated carbon and ordered mesoporous carbon) due to the unique thin layer structure of GO. Because of the high heat storage capacity and the moderate phase change temperature, the PEG–GO composite is a promising heat energy storage candidate at mild temperature.
Co-reporter:Junzhi Yang, Dichen Li, He Fu, Gongbiao Xin, Jie Zheng and Xingguo Li
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 8) pp:NaN2863-2863
Publication Date(Web):2011/12/21
DOI:10.1039/C2CP23776H
Nano-composites of LiNH2–LiH–xMg(BH4)2 (0 ≤ x ≤ 2) were prepared by plasma metal reaction followed by a nucleation growth method. Highly reactive LiNH2–LiH hollow nanoparticles offered a favorable nucleus during a precipitation process of liquid Mg(BH4)2·OEt2. The electron microscopy results suggested that more than 90% of the obtained nano-composites were in the range 200–400 nm. Because of the short diffusion distance and ternary mixture self-catalyzing effect, this material possesses enhanced hydrogen (de)sorption attributes, including facile low-temperature kinetics, impure gases attenuation and partial reversibility. The optimal hydrogen storage properties were found at the composition of LiNH2–LiH–0.5Mg(BH4)2, which was tentatively attributed to a Li4(NH2)2(BH4)2 intermediate. 5.3 wt% hydrogen desorption could be recorded at 150 °C, with the first 2.2 wt% release being reversible. This work suggests that controlled in situ hybridization combined with formula optimization can improve hydrogen storage properties.
Co-reporter:Tong Liu, Chenggong Qin, Tongwen Zhang, Yurong Cao, Mu Zhu and Xingguo Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 37) pp:NaN19838-19838
Publication Date(Web):2012/08/03
DOI:10.1039/C2JM33911K
In order to improve the hydrogen storage properties of Mg, Mg@Mg17Al12 ultrafine particles (UFPs) with 7, 22 and 27 at% Al have been successfully prepared by a hydrogen plasma–metal reaction (HPMR) approach. These UFPs are nearly spherical in shape with an average size of about 150 nm. The Mg particle core is a single crystal, and the Mg17Al12 particle shell of 2–5 nm thickness effectively suppresses the formation of MgO. The formation mechanism of the core–shell structure is interpreted in terms of Mg–Al phase transformation. The Mg17Al12 shell disproportionates into MgH2 and Al upon hydrogenation, and is recovered after hydrogen release. The morphology and size of these UFPs are not obviously changed during the sorption cycle, whereas the Mg particle core changes from single crystal into the polycrystalline form of 2–4 nm size. The hydrogen sorption kinetics and storage capacity of the Mg@Mg17Al12 UFPs decreased with increasing Al content. Mg–7 at.% Al can absorb 5.7 wt% H2 at 523 K and 7.0 wt% H2 at 673 K. It can release 6.0 wt% H2 within 30 minutes at 623 K and 6.2 wt% H2 within 3 minutes at 673 K. The catalytic effect and oxidation resistance of the Mg17Al12 shell, and the nanostructure of the Mg core accelerate the hydrogen diffusion, with low hydrogen absorption and desorption activation energies of 49.3 and 105.5 kJ mol−1, respectively.
Co-reporter:Xiaojuan Wang, Junwen Zhou, He Fu, Wei Li, Xinxin Fan, Gongbiao Xin, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2014 - vol. 2(Issue 34) pp:NaN14070-14070
Publication Date(Web):2014/06/24
DOI:10.1039/C4TA01506A
Developing noble metal free catalysts for the oxygen reduction reaction (ORR) is of critical importance for the production of low cost polymer electrolyte membrane fuel cells. In this paper, metal organic frameworks (MOFs) are used as precursors to synthesize ORR catalysts via pyrolysis in an inert atmosphere. The ORR performance is found to be closely associated with the metal/ligand combination in MOFs. The Co-imidazole based MOF (ZIF-67) derived catalyst exhibits the best ORR activity in both alkaline and acidic electrolytes. The Co cations coordinated by the aromatic nitrogen ligands in ZIF-67 may assist the formation of ORR active sites in the derived catalyst. The best ORR performance is obtained when the porosity of the derived catalyst is maximized, by optimizing the pyrolysis temperature and the acid leaching process. The performance of the best MOF derived catalyst is comparable to that of Pt/C in both alkaline and acidic electrolytes.
Co-reporter:Teng Wang, Qianyu Zhou, Xiaojuan Wang, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 32) pp:NaN16439-16439
Publication Date(Web):2015/07/09
DOI:10.1039/C5TA04001A
Pyrolysis of a Ni based metal organic framework in NH3 yields Ni nanoparticles with surface nitridation together with thin carbon coating layers. The subtle surface modification significantly improves the catalytic performance for the hydrogen evolution reaction (HER). The surface modified Ni nanoparticles show a low overpotential of only 88 mV at a current density of 20 mA cm−2, which is one of the most efficient HER catalysts based on metallic Ni reported so far. The results suggest that controlled pyrolysis of MOFs is an effective method to prepare highly efficient noble metal free HER catalysts.
Co-reporter:Junwen Zhou, Xiaosong Yu, Xinxin Fan, Xiaojuan Wang, Haiwei Li, Yuanyuan Zhang, Wei Li, Jie Zheng, Bo Wang and Xingguo Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8275-8275
Publication Date(Web):2015/03/06
DOI:10.1039/C5TA00524H
The particle size of an electrode material is known to play an essential role in its electrochemical performance in Li-ion batteries. In Li–S batteries, porous host materials are applied to store sulfur and suppress the escape of polysulfides; yet the particle size of the host as an important parameter remains largely unexplored. Herein we chose ZIF-8, a metal–organic framework (MOF) proved promising for sulfur storage, as the proof-of-concept prototype, and systematically synthesized five sets of ZIF-8 samples of different particle sizes (from <20 nm to >1 μm), using them as S@MOF cathodes. The results show that sulfur utilization increases monotonically with the decrease of ZIF-8 particle size (<20 nm: >950 mA h g−1 at 0.5 C), while the best cycling stability (75% over 250 cycles at 0.5 C) is achieved with a moderate size (∼200 nm).
Co-reporter:Xinghua Chang, Wei Li, Junfeng Yang, Li Xu, Jie Zheng and Xingguo Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 7) pp:NaN3528-3528
Publication Date(Web):2014/12/23
DOI:10.1039/C4TA06334A
Plasma reactions are very effective in the preparation of both silicon and carbon materials. However, Si/C composites, which are highly attractive as the anode material in lithium ion batteries, are difficult to be prepared using plasma due to the strong tendency of silicon carbide (SiC) formation. Here we effectively inhibit the SiC formation by generating reactive Si and C species in separated plasma zones and by using a solid graphite carbon precursor. Homogeneous Si/C nanocomposites with excellent lithium storage performance are obtained by one step plasma deposition at room temperature, which retain a high capacity of 1760 and 1460 mA h g−1 after more than 400 cycles at a charge/discharge rate of 2.0 and 4.0 A g−1, respectively.
Co-reporter:Gongbiao Xin, Xiaojuan Wang, Chongyun Wang, Jie Zheng and Xingguo Li
Dalton Transactions 2013 - vol. 42(Issue 48) pp:NaN16696-16696
Publication Date(Web):2013/10/08
DOI:10.1039/C3DT52482E
An alkaline primary Mg–air battery made from a porous Mg thin film displayed superior discharge performances, including a flat discharge plateau, a high open-circuit voltage of 1.41 V and a large discharge capacity of 821 mAh g−1, suggesting that the electrochemical performances of Mg–air batteries can be improved by controlling the Mg anode morphology.
Co-reporter:Gongbiao Xin, Junzhi Yang, Guoqing Zhang, Jie Zheng and Xingguo Li
Dalton Transactions 2012 - vol. 41(Issue 38) pp:NaN11558-11558
Publication Date(Web):2012/05/21
DOI:10.1039/C2DT30946G
We prepared a series of nano-sized Mg–Al–Pd trilayer films and investigated their hydrogen storage properties under mild conditions. Results showed that Al 1 nm sample had the best absorption kinetics and excellent optical properties at room temperature, making it a promising candidate for hydrogen sensors and smart windows.
Co-reporter:Gongbiao Xin, Junzhi Yang, Chongyun Wang, Jie Zheng and Xingguo Li
Dalton Transactions 2012 - vol. 41(Issue 22) pp:NaN6790-6790
Publication Date(Web):2012/03/19
DOI:10.1039/C2DT30253E
In this paper, a series of Mg–Ti–Pd trilayer films with various thicknesses of the Ti interlayer were prepared by magnetron sputtering. The trilayer films could be reversibly (de)hydrogenated at room temperature. The relationship between structure and properties of Mg–Ti–Pd trilayer films was comprehensively investigated. Our studies showed that the hydrogen storage properties of Mg–Pd films were significantly improved with the addition of a Ti interlayer. The optimal hydrogenation properties were obtained when the Ti interlayer was 1 nm. The superior hydrogenation properties achieved by introduction of the Ti interlayer could be attributed to several aspects: prevention of Mg–Pd alloying; catalytic dissociation of H2 molecules and provision of heterogeneous nucleation sites. These results were elucidative for the development of high performance intermetallic hydrogen storage materials and thin film based functional devices.
Co-reporter:Jianglan Qu, Yang Liu, Gongbiao Xin, Jie Zheng and Xingguo Li
Dalton Transactions 2014 - vol. 43(Issue 15) pp:NaN5912-5912
Publication Date(Web):2014/01/31
DOI:10.1039/C3DT53646G
Pd–Mg–Pd thin films with variable thickness of Mg layers were prepared. Their optical and electrical changes in both gasochromic and chemochromic processes were compared to investigate the kinetics of Mg-based thin films at room temperature. Hydrogen absorption and desorption kinetics of Pd–Mg–Pd thin films were strongly dependent on the thickness of the Mg layer. Especially, when the thickness was lowered to 60 nm, a MgH2 layer formed immediately after exposure to H2 at room temperature, while a Mg layer was rapidly generated during hydrogen desorption in ambient air. By means of optical and electrical resistance measurements, we found that the diffusion process contributed significantly to hydrogen absorption and desorption. The remarkable absorption and desorption kinetics at room temperature reported here suggested promising applications in Mg-based energy-efficient devices and hydrogen sensors.
Co-reporter:Jing Huang, Jin Xie, Kai Chen, Lihong Bu, Seulki Lee, Zhen Cheng, Xingguo Li and Xiaoyuan Chen
Chemical Communications 2010 - vol. 46(Issue 36) pp:NaN6686-6686
Publication Date(Web):2010/08/23
DOI:10.1039/C0CC01041C
We report in this Communication a facile, two-step surface modification strategy to achieve manganese oxide nanoparticles with prominent MRI T1 contrast. In a U87MG glioblastoma xenograft model, we confirmed that the particles can accumulate efficiently in tumor area to induce effective T1 signal alteration.
Co-reporter:Jie Zheng, DengChen Yang, Wei Li, He Fu and Xingguo Li
Chemical Communications 2013 - vol. 49(Issue 82) pp:NaN9439-9439
Publication Date(Web):2013/08/12
DOI:10.1039/C3CC45021J
H2 generation from the reaction between Mg nanoparticles and water can be significantly promoted by low cost chlorides. The promotion effect exhibits strong correlation with the OH− affinity of the corresponding cation. This interesting observation offers a simple and effective solution to portable H2 generation under mild conditions.
Co-reporter:Wei Li, Jie Zheng, Tiankai Chen, Teng Wang, Xiaojuan Wang and Xingguo Li
Chemical Communications 2014 - vol. 50(Issue 16) pp:NaN2054-2054
Publication Date(Web):2013/12/23
DOI:10.1039/C3CC47719C
We employ a tandem plasma reaction method to prepare ultrafine Ge nanoparticles embedded in a carbon matrix in one step. The obtained Ge–C composite exhibits very high lithium storage capacity (980 mA h g−1) and excellent cycling performance (less than 2% capacity loss in 100 cycles).
Co-reporter:Gongbiao Xin, Huiping Yuan, Lijun Jiang, Shumao Wang, Xiaopeng Liu and Xingguo Li
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 20) pp:NaN13612-13612
Publication Date(Web):2015/04/27
DOI:10.1039/C5CP01897H
In this paper, the gaseous and electrochemical hydrogen storage properties of 200 nm Mg–Pd thin films with different morphologies have been investigated. The results show that Mg–Pd films become porous with the increase of substrate temperature. Porous Mg–Pd films exhibit superior gaseous and electrochemical hydrogen storage behaviors under mild conditions, including rapid hydrogen sorption kinetics, a large hydrogen storage amount, high electrochemical discharge capacity, and a fast hydrogen diffusion rate. The excellent behaviors of porous Mg–Pd films might be ascribed to the significantly shortened hydrogen diffusion paths and the large contact areas between the hydrogen gas and the solid Mg phases, which are elucidative for the development and applications of thick Mg–Pd films.
