Co-reporter:Yixian Huang;Yu Tong;Chen Wang
Industrial & Engineering Chemistry Research January 21, 2015 Volume 54(Issue 2) pp:705-711
Publication Date(Web):2017-2-22
DOI:10.1021/ie503502g
Hydrophilic ionic liquids, 1-alkyl-3-methylimidazolium chloride ([Cnmim]Cl, n = 12, 14, and 16) are tested to precipitate Pt(IV) from hydrochloric acid medium. Meanwhile the Pt(IV) extractions are performed with hydrophobic ionic liquids, including 1-alkyl-3-methylimidazolium hexafluorophosphate ([Cnmim]PF6, n = 4, 6, and 8) and 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C8mim]NTf2). Based on Job’s method, infrared spectra, and 1H NMR analysis, the anion-exchange mechanism is confirmed during the Pt(IV) precipitation. The mixed hydrophilic–hydrophobic ionic liquids ([Cnmim]Cl/[C8mim]PF6) are developed for Pt(IV) extraction, which significantly increase the Pt(IV) extractability compared to the single hydrophobic ionic liquid. Under the optimum conditions, the [C16mim]Cl/[C8mim]PF6 system shows high extractability as well as outstanding selectivity for Pt(IV) over the base metals (Mn(II), Cu(II), Co(II), Ni(II), Fe(III), and Al(III)). By reductive stripping, Pt(IV) in the organic phase can be stripped in the form of platinum powders using hydrazine hydrate; at the same time [C16mim]Cl is regenerated in the organic phase. The mixed [C16mim]Cl/[C8mim]PF6 ionic liquids can be reused to extract Pt(IV). Therefore, the method is highly effective, selective, and recyclable to extract Pt(IV) and recover metal platinum.
Co-reporter:Xiaolu Yin, Huilin Yi, Qi Wang, Yudong Wang, Xu Sun, Cheng Lv, Jinxin Guo, Yanzhao Yang
Hydrometallurgy 2017 Volume 174(Volume 174) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.hydromet.2017.10.009
•Pd (II), Pt (IV), Rh (III) and Ir (IV) were separated with low-viscosity HMImT by microextraction.•Ion association mechanism of Pt (IV) was proved by theoretical calculation and experiments.•Novel precipitating-calcining method was designed to obtain Rh2O3, Pd and Pt2O.•The separation process was simple and economical.In this study, palladium (II), platinum (IV), rhodium (III) and iridium (IV) were sequentially separated with 1-hexyl-3-methylimidazole-2-thione (HMImT) from aqueous hydrochloric acid media by adjustment of hydrochloric acid concentration or in the presence of tin (II) chloride using environmental-friendly microextraction method. It is the first time to use sole extractant to selectively separate four platinum group metals from aqueous solution. Through condition optimization, HMImT shows outstanding extraction capacity (Pd 0.54 mmol/g, Pt 0.14 mmol/g, Rh 0.82 mmol/g) and high extraction percentage to palladium (99.4%), platinum (99.8%), rhodium (99.6%) respectively. The separation coefficient exceeds 10,000 and obtained metals purity reaches 99%. Based on Job's method, FT-IR spectra, UV–vis spectra, 1H NMR spectra and theoretical natural population analysis (NPA), the anion exchange mechanism of HMImT on Pt (IV) extraction was confirmed. By precipitating-calcining method palladium (II), platinum (IV) and rhodium (III) could be recycled in the form of Rh2O3, Pd and Pt2O.Download high-res image (146KB)Download full-size image
Co-reporter:Wenhui Liu;Qi Wang;Yan Zheng;Shubin Wang;Yan Yan
Dalton Transactions 2017 vol. 46(Issue 22) pp:7210-7218
Publication Date(Web):2017/06/06
DOI:10.1039/C7DT01142C
In this study, a method of one-step separation and recycling of high purity Pd(II) and Pt(IV) using an ionic liquid, 1-butyl-3-benzimidazolium bromate ([HBBIm]Br), was investigated. The effects of [HBBIm]Br concentration, initial metal concentration, and loading capacity of [HBBIm]Br were examined in detail. It was observed that [HBBIm]Br was a very effective extractant for selectively extracting Pd(II) and precipitating Pt(IV). Through selectively extracting Pd(II) and precipitating Pt(IV), each metal with high purity was separately obtained from mixed Pd(II) and Pt(IV) multi-metal solution. The method of one-step separation of Pd(II) and Pt(IV) is simple and convenient. The anion exchange mechanism between [HBBIm]Br and Pt(IV) was proven through Job's method and FTIR and 1H NMR spectroscopies. The coordination mechanism between [HBBIm]Br and Pd(II) was demonstrated via single X-ray diffraction and was found to be robust and distinct, as supported by the ab initio quantum-chemical studies. The crystals of the [PdBr2 ·2BBIm] complex were formed first. Moreover, the influence of the concentrations of hydrochloric acid, sodium chloride, and sodium nitrate on the precipitation of Pt(IV) and extraction of Pd(II) was studied herein. It was found that only the concentration of H+ could inhibit the separation of Pt(IV) because H+ could attract the anion PtCl62−; thus, the exchange (anion exchange mechanism) between the anions PtCl62− and Br− was prevented. However, both the concentration of H+ and Cl− can obviously inhibit the extraction of Pd(II) because H+ and Cl− are the reaction products and increasing their concentration can inhibit the progress of the reaction (coordination mechanism).
Co-reporter:Zeyang Xiang;Yan Zheng;Hong Zhang;Yan Yan;Xiaoyu Yang;Xia Xin
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 14) pp:6180-6186
Publication Date(Web):2017/07/10
DOI:10.1039/C7NJ00551B
Microemulsions consisting of ionic liquid-type imidazolium gemini surfactants with different spacer lengths ([C14-n-C14im]Br2, n = 2, 4, 6), cyclohexane, n-hexyl alcohol and hydrochloric acid solution, were investigated for Au(III) extraction. [C14-n-C14im]Br2 in the microemulsion played a dual role as surfactant and extractant. The extraction efficiency (E%) of the [C14-n-C14im]Br2/cyclohexane/n-hexyl alcohol/HCl microemulsion system for Au was above 99% under optimal conditions. The results of our study indicated that the Au(III) extraction ability of the three different [C14-n-C14im]Br2 with different spacer lengths was better with longer a spacer. The mechanism for the Au(III) extraction by [C14-n-C14im]Br2 was confirmed to be based on an anion-exchange process by the continuous variation method and spectroscopic analysis (UV-Vis, FT-IR, 1H-NMR). The FT-IR spectra indicated that the better extraction ability of [C14-n-C14im]Br2 for Au(III) was positively correlated with the spacer length, due to a less significant steric effect of the methylene groups in surfactants with longer spacers. The electric conductivity values of the [C14-n-C14im]Br2 microemulsions indicated that surfactants with longer spacers can ionize to a higher extent to give more [C14-n-C14im]2+ cations and Br− anions, thus promoting anion-exchange and further increasing E%.
Co-reporter:Hong Zhang, Xiaoyu Yang, Zhaohui Liu, Yanzhao Yang
Chemical Engineering Journal 2017 Volume 308(Volume 308) pp:
Publication Date(Web):15 January 2017
DOI:10.1016/j.cej.2016.09.027
•Ru(III) was firstly recovered by 2-Mercaptobenzothiazolate-functionalized ionic liquid based CPE system.•Influence factors in CPE system was studied in detail.•Superior extractability of Ru(III) was achieved under optimum conditions.•Mechanism on Ru(III) extraction during CPE process was investigated by UV–vis and FT-IR.An arisen and environment-friendly method of cloud point extraction (CPE) which involved Octylphenoxypolyethoxyethanol (TX-114) as surfactant and 2-Mercaptobenzothiazole-functionalized ionic liquid as extractant was carried out to separate Ru(III) from aqueous phase to bottom surfactant phase for the first time. A host of variable (e.g., the extractant concentration, hydrochloric acid concentration, nitric acid concentration, TX-114 mass fraction, TX-114 volume and sodium chloride concentration) were evaluated and optimized to investigate the extraction behavior. At optimized experimental conditions, the extraction percentage of Ru(III) was found to be 82%, together with the enrichment factor of 40. A special complexation extraction mechanism of Ru(III) in CPE process was studied systemically and confirmed via job method, UV–vis spectrum and FT-IR spectrum in detail. Taking together, the rational-designed functional ionic liquid as a novel extractant exhibited superior extractability for Ru(III) in CPE system.Download high-res image (155KB)Download full-size image
Co-reporter:Yonghua Guo, Huiying Wei, Genyuan Zhao, Xueqin Ma, Wenshuang Zhu, Yanzhao Yang
Fuel 2017 Volume 206(Volume 206) pp:
Publication Date(Web):15 October 2017
DOI:10.1016/j.fuel.2017.06.034
•A Mn-Co-Ce-Ox catalyst was synthesized and efficient on NO and CO oxidation under low temperature.•The catalysts were characterized by XRD, BET, H2-TPR and XPS methods.•The mechanism of dual redox cycles in the Mn-Co-Ce-Ox catalyst was proposed.•The catalyst showed outstanding sulfur tolerance and thermal stability.A series of Mn-Co-Ce-Ox were prepared using co-precipitation method and tested for low temperature catalytic oxidation of NO and CO with O2. The best catalytic result was obtained by Mn0.2Co0.3Ce0.5 catalyst, which yielded 100% NO and CO conversion at 185 °C and 105 °C under space velocity at 60,000 h−1 respectively. XRD, BET, TEM, H2-TPR, XPS and Raman were used for the structure and redox properties investigation of mixed oxide. The catalyst characterization suggested that the high catalytic oxidation performance was attributed to dual redox cycles (Mn3+ + Co3+ ↔ Mn4+ + Co2+, Mn3+ + Ce4+ ↔ Mn4+ + Ce3+). In the SO2 and H2O poisoning test, 67% of NO converted to NO2 over the Mn0.3Co0.2Ce0.5 catalysts and recovered to 82% quickly, which displayed high resistance against H2O and SO2. The catalyst shows good stability between 24 h test.
Co-reporter:Zhaohua Song, Xia Xin, Jinglin Shen, Jianmei Jiao, Congxin Xia, Shubing Wang, Yanzhao Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2017 Volume 518(Volume 518) pp:
Publication Date(Web):5 April 2017
DOI:10.1016/j.colsurfa.2017.01.004
•The effects of amino acids on the phase behavior of ionic liquid-type imidazolium surfactant were investigated.•With the addition of Lys, C14mimBr LLC transformed to worm-like micelles.•For C14mimBr/Arg system, it remained the hexagonal phases.•Our work contributes to a better understanding of the effect of amino acids on the influence of surfactant aggregates.The effects of alkaline amino acids l-Lysine (l-Lys) and l-Arginine (l-Arg) on the lyotropic liquid crystal (LLC) behavior of ionic liquid-type imidazolium surfactant (1-tetradecyl-3-methylimidazolium bromide, C14mimBr) were investigated systematically. The corresponding properties were investigated by polarized optical microscopy (POM), small angle X-ray scattering (SAXS), field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy and rheological measurements. The results indicated that with the introduction of l-Lys, LLC phase of C14mimBr gradually undergoes the transition to an isotropic homogeneous phase, which demonstrated to be worm-like micelles (WLMs). While for C14mimBr/l-Arg system, it remained the hexagonal phases and merely induced the variation of the mechanical strength of C14mimBr LLCs. It can be speculated that the balance between electrostatic interaction, H-bond interaction, and hydrophobic interaction plays an important role in the phase transition of C14mimBr/amino acids. Our work can contribute to a better understanding of the effect of the additions especially amino acids on the influence of the surfactant aggregates and their macroscopic properties, which maybe open the door for wide applications in the biological system.Schematic illustrations of the phase transition between LLCs and the micelle solution by the introducing of amino acids.Download high-res image (345KB)Download full-size image
Co-reporter:Yan Yan;Qi Wang;Zeyang Xiang;Yan Zheng;Shubin Wang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 17) pp:8985-8992
Publication Date(Web):2017/08/21
DOI:10.1039/C7NJ02361H
In the process of recovering platinum group metals by extraction, separation of Pt and Ir is very difficult because Pt(IV) and Ir(IV) show similar chemical properties and extraction behaviours in hydrochloric acid medium. In this paper, a betaine-based ionic liquid [C6bet]Br was firstly applied to the separation of Pt(IV) and Ir(IV). [C6bet]Br showed remarkable precipitation performance of Pt(IV) and Ir(IV). The impactful extraction was realized by importing [C6mim][NTF2] as the hydrophobic phase with extraction efficiencies of ca. 99% and 88% under optimal conditions. A selective reduction process for Ir(IV) was firstly proposed for the separation of these two similar PGMs by using hydroxylamine hydrochloride (NH2OH·HCl). The mechanism of extracting Pt(IV)/Ir(IV) using [C6bet]Br was confirmed to be an anion-exchange process by spectroscopic analysis (UV-Vis, FT-IR, 1H NMR) and the method of continuous variation. The electrostatic potential map of [C6bet]Br was calculated for the first time to confirm the anion-exchange mechanism. 8 M HCl was effective for the back extraction of Pt(IV) and Ir(IV).
Co-reporter:Xiaolu Yin;Qi Wang;Shubin Wang;Hong Zhang;Jinxin Guo
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 18) pp:10054-10061
Publication Date(Web):2017/09/11
DOI:10.1039/C7NJ01959A
1-Hexyl-3-methylimidazole-2-thione (HMImT), a low-viscosity extractant, was firstly synthesized and used to extract rhodium(I). The negligible solubility of HMImT in solution was measured by HPLC to be about 0.015%. In the extraction process, rhodium(III) in solution was activated into rhodium(I) by SnCl2 to improve extraction percentage, which was confirmed by XPS spectra. Under optimum conditions, the extraction percentage reached 99.6%. The neutral complexing mechanism was confirmed by UV-vis spectra, 1H NMR spectra, titration method and FT-IR spectra. Quantum chemical calculations based on density functional theory (DFT) were also performed to support the results from a theoretical perspective. The extraction process was modeled by Langmuir (R2 = 0.998), Freundlich (R2 = 0.972) and Dubinin–Radushkevich isotherms (R2 = 0.990). According to the model results, the monolayer absorption capacity was 2.82 mmol g−1, and the mean free energy was obtained as 9.8 kJ mol−1. The thermodynamic parameters of ΔG, ΔH and ΔS showed that the extraction process was spontaneous and exothermic. Pseudo-second-order kinetics well fitted the experimental data (R2 = 0.996). In addition, HMImT possesses high selectivity to Rh(I) rather than other base metals during extraction. In summary, HMImT with low dissipation, excellent extractability and high selectivity for rhodium(I) extraction will hold great promise and potential in the separation field.
Co-reporter:Wei Liu, Ke Tang, Ming Lin, Lay Ting Ong June, Shi-Qiang Bai, David James Young, Xu Li, Yan-Zhao Yang and T. S. Andy Hor
Nanoscale 2016 vol. 8(Issue 18) pp:9521-9526
Publication Date(Web):13 Apr 2016
DOI:10.1039/C6NR02383E
Solvothermal synthesis of Cu2O cubes from Cu(OAc)2 in ethanol provided templates for tunable formation of novel multicomponent composites: hollow CeO2–Cu2O (1), core–shell NiO@Cu2O (2) and hollow CeO2–NiO–Cu2O (3). Composites 1–3 catalyze the oxidation of CO at a lower temperature than the parent Cu2O cubes.
Co-reporter:Wei Liu, Wenzhi Wang, Ke Tang, Jinxin Guo, Yuqing Ren, Shuping Wang, Lijun Feng and Yanzhao Yang
Catalysis Science & Technology 2016 vol. 6(Issue 7) pp:2427-2434
Publication Date(Web):19 Nov 2015
DOI:10.1039/C5CY01241D
In this paper, a series of well-dispersed nickel–ceria catalysts with high surface area were successfully fabricated using a simple solvothermal approach and characterized by XRD, TEM, EDS, N2-sorption, Raman and TPR techniques. The results show that the amount of nickel species can have an impact on the morphology of the nickel–ceria catalysts, i.e. the hollow structure, particle size and porous structures. The prepared nickel–ceria samples (with the atomic ratio Ni:Ce (At% (Ni/Ce)) at approximately 6.58%) exhibit high catalytic performance in carbon monoxide (CO) oxidation with 100% conversion at 200 °C. The XRD, Raman, XPS and H2-TPR data confirm that the nickel species are the main promoting factor in the catalysis, including the doped nickel species, highly dispersed free NiO and the interfacial Ni–[O]–Ce structures. Further, the as-prepared nickel–ceria catalysts show high stability in the catalysis.
Co-reporter:Shubin Wang, Yan Zheng, Hong Zhang, Yan Yan, Xia Xin, and Yanzhao Yang
Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 10) pp:2790-2797
Publication Date(Web):February 25, 2016
DOI:10.1021/acs.iecr.5b04115
A microemulsion with hydrochloric acid solution as the polar phase, n-heptane as the continuous phase, [C14-4-C14im]Br2 as an ionic-liquid-type imidazolium gemini surfactant and extractant, and n-amyl alcohol as cosurfactant was studied on Au(III) extraction. Compared to its corresponding monomer [C14-mim]Br-based microemulsion for Au(III) extraction, the [C14-4-C14im]Br2-based microemulsion system showed excellent extractability of Au(III). The anion-exchange mechanism of Au(III) extraction was confirmed by the slope method and spectrum analysis (UV–vis, FT-IR, and 1H NMR). Main influence factors such as phase ratio, extraction equilibrium time, amyl alcohol volume fraction, and the concentration of ionic liquid on the extraction efficiency (E%) were explored. Moreover, [C14-4-C14im]Br2-based water-in-oil microemulsion had high selectivity over a multimetal ion solution (Co (II), Cu(II), Fe(III), Ni(II), Sn(IV), and Al(III)). Therefore, it is indicated that [C14-4-C14im]Br2-based microemulsion provides an effective and potential approach for the separation and purification of Au(III) from HCl solution.
Co-reporter:Wenshuang Zhu, Ke Tang, Jing Li, Wei Liu, Xiaoran Niu, Genyuan Zhao, Xueqin Ma, Zhaohui Liu, Huiying Wei and Yanzhao Yang
RSC Advances 2016 vol. 6(Issue 52) pp:46966-46971
Publication Date(Web):06 May 2016
DOI:10.1039/C6RA08204A
In this paper, copper doped ceria porous nanospheres were synthesized using carbon nanospheres as a hard template via a homogenous precipitation method at low temperature. The results showed that the copper-doped ceria has undergone a morphology transformation from the initial double-shell spheres to hollow spheres as the copper doping concentration increased from 0 to 7.5%mol. Notably, the Cu/Ce + Cu atomic ratio in the final products was approximately five times the initial design ratio, which confirmed an efficient utilization of copper in this system. Furthermore, the copper-ceria catalysts exhibited enhanced catalytic performance towards CO conversion when compared with pure ceria catalysts (e.g., for the optimal catalysts, the complete conversion temperature was 160 °C, for the pure catalysts, complete conversion temperature was 300 °C). Through the analysis of the catalysts structure, we proved that the superior catalytic performance was derived from a combination of CuOx clusters and copper ions in the Cu–[Ox]–Ce bulk phase.
Co-reporter:Shubin Wang, Xia Xin, Han Zhang, Jinglin Shen, Yan Zheng, Zhaohua Song and Yanzhao Yang
RSC Advances 2016 vol. 6(Issue 34) pp:28156-28164
Publication Date(Web):07 Mar 2016
DOI:10.1039/C6RA02450E
A facile and versatile method for the synthesis of stable monodisperse colloidal gold nanoparticles was developed using a water-in-oil microemulsion-templating strategy. The water-in-oil microemulsion was composed of cationic imidazolium gemini surfactant [C14-4-C14im]Br2, 1-heptane, 1-pentanol and HAuCl4 aqueous solution. The properties of these Au nanoparticles have been fully characterized using transmission electron microscopy (TEM), high-resolution TEM (HR-TEM) observations, X-ray diffraction (XRD), and UV-vis measurements. It can be observed that the monodisperse gold nanoparticles possess a hexagonal close-packed mode and can further aggregate to a rotundity which is shaped like a micro emulsion template while we can not get this kind of morphology using other templates such as [C14min]Br, sodium 1-tetradecanesulphonate or tetradecyltrimethylammonium bromide (TTAB). Moreover, the catalytic efficiency of the gold nanoparticles was evaluated by using the reduction of 4-nitroaniline (4-NA) by potassium borohydride (KBH4) in aqueous solution and electrochemical reduction of hydrogen peroxide (H2O2). These Au nanoparticles possess excellent properties making them fascinating candidates for a variety of applications such as catalysis and life science.
Co-reporter:Zhaohua Song, Xia Xin, Jinglin Shen, Han Zhang, Shubin Wang and Yanzhao Yang
RSC Advances 2016 vol. 6(Issue 4) pp:2966-2973
Publication Date(Web):23 Dec 2015
DOI:10.1039/C5RA21979E
In this work, the effects of four imidazolium-based surfactants with different lengths of hydrophobic alkyl tails ([C2mim]Br, [C8mim]Br, [C12mim]Br, and [C14mim]Br) on the self-assembly behaviors of the biological surfactant sodium deoxycholate (NaDC) in sodium phosphate buffer (pH = 7) were investigated systematically. The microstructures and properties of NaDC/CnmimBr (n = 2, 8, 12, 14) mixed systems were characterized using transmission electron microscopy (TEM), field emission-scanning electron microscopy (FE-SEM), polarized optical microscopy (POM) observations, Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD) and rheological measurements. The roles of the hydrophobic chain length, the chiral rigid steroid center, and the electrostatic interaction for the evolution of phase behavior are clearly described. The results indicated that the long-chain imidazolium-based surfactants ([Cnmim]Br, n ≥ 8) weakened the gel of NaDC, while C2mimBr strengthened the gel behavior of NaDC and even can form microcrystals. The super-hydrogels formed by these systems may act as promising adsorbents for the removal of heavy-metal ions from industrial sewage.
Co-reporter:Shubin Wang, Xiaolu Yin, Yan Yan, Zeyang Xiang, Peng Liu, Yao Chen, Xia Xin, and Yanzhao Yang
Industrial & Engineering Chemistry Research 2016 Volume 55(Issue 29) pp:8207-8214
Publication Date(Web):July 7, 2016
DOI:10.1021/acs.iecr.6b01712
A kind of self-assembled vesicles that composed of ionic liquid-type cationic gemini surfactant (C3H6-α, ω-(Me2N+C12H25Cl–)2, 12-3-12) and anionic biological surfactant (sodium deoxycholate, SDC) were constructed for Au(III) extraction. The appearance and microstructure of vesicles system were characterized by visual and TEM images. Compared to the zeta potential of pure vesicles system (+45 ± 1 mV), zeta potential of gold-loaded vesicles system reduced 15 ± 1 mv (changed to +30 ± 1 mV), which confirmed the mechanism of Au(III) was effectively extracted by vesicles through electrostatic interaction. The main influence factors including extraction equilibrium time, surfactants concentration, NaCl concentration, and pH on the extraction efficiency (E%) were explored. Furthermore, an effective method was devoted for gold(III) stripping. Through stepwise extraction and ligand-modified vesicles system, Au(III), Cu(II), and Fe(III) were separated from a mixed solution successfully. In short, an effective and potential approach for the separation of Au(III) from HCl solution was investigated in our work, which can be helpful for gold recovery and environmental improvement.
Co-reporter:Genyuan Zhao, Jing Li, Xiaoran Niu, Ke Tang, Shuping Wang, Wenshuang Zhu, Xueqin Ma, Miaoyan Ru and Yanzhao Yang
New Journal of Chemistry 2016 vol. 40(Issue 4) pp:3491-3498
Publication Date(Web):12 Feb 2016
DOI:10.1039/C5NJ03694A
In this paper, a facile solvothermal method has been employed to synthesize monodispersed Mn-doped Fe2O3 with shuttle-like nanostructure. The structure of the samples was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscope (SEM). Manganese species doped into the Fe2O3 lattice were then confirmed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometry (EDS). The doping of Mn ions led to the formation of the shuttle-like structure and increase of the surface area compared to pure Fe2O3. PVP also played an important role in the formation of the shuttle-like structure. The mechanism for the growth of Mn-doped Fe2O3 was proposed as the recrystallization of metastable precursors (RMP) route. H2-TPR measurement revealed better reduction behavior of the Mn-doped Fe2O3. Finally, the as-prepared Mn-doped Fe2O3 exhibited excellent catalytic performance and cycling stability towards CO oxidation.
Co-reporter:Yan Zheng, Liying Fang, Yan Yan, Shujie Lin, Zhaohui Liu, Yanzhao Yang
Separation and Purification Technology 2016 Volume 169() pp:289-295
Publication Date(Web):1 September 2016
DOI:10.1016/j.seppur.2016.06.022
•[Si4mim]Cl is first used for the construction of the W/O microemulsion system.•The [Si4mim]Cl/n-heptane/n-hexanol/NaCl system is applied for Pd (II) extraction firstly.•The microemulsion shows high extractability of 98% for Pd (II).•The extraction percentage of several metals is less than 12% by the microemulsion.•Pd (II) is easily stripped using NaCl from the Pd (II)-loaded microemulsion phase.The silicone ionic liquid, 1-methyl-3-[tri-(trimethylsiloxy)]silylpropyl-imidazolium chloride ([Si4mim]Cl), was first used for the construction of the W/O microemulsion system and the [Si4mim]Cl/n-heptane/n-hexanol/NaCl microemulsion system was applied for palladium extraction for the first time. The stability of [Si4mim]Cl/n-heptane/n-hexanol/NaCl microemulsion system was characterized by the Turbiscan Lab. For the Pd (II) extraction by the [Si4mim]Cl/n-heptane/n-hexanol/NaCl microemulsion system, primary parameters (namely, the vibration time, the [Si4mim]Cl concentration, the phase ratio and the additives) affecting the palladium extraction was investigated to optimize the process. Under the optimum conditions, the extraction percentage of Pd (II) is up to 98%. Afterwards, the ionic-exchange mechanism of Pd (II) extraction by the [Si4mim]Cl/n-heptane/n-hexanol/NaCl microemulsion system was confirmed by the Job Method and analyzed by FT-IR spectra. The stripping of Pd (II) from the microemulsion phase was also studied using the NaCl solutions, indicating a high stripping efficiency. At last, the selectivity of the [Si4mim]Cl/n-heptane/n-hexanol/NaCl microemulsion system to Pd (II) from other metals (Cu (II), Co (II), Ni (II), Fe (III), Al (III) Zn (II), Ce (III), Li (I), Mg (II) and Sn (IV)) was demonstrated to be quite high. The results of our work indicate that the [Si4mim]Cl/n-heptane/n-hexanol/NaCl microemulsion system is a promising approach for Pd (II) extraction.
Co-reporter:Ke Tang, Wei Liu, Jing Li, Jinxin Guo, Jingcai Zhang, Shuping Wang, Shengli Niu, and Yanzhao Yang
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 48) pp:26839
Publication Date(Web):November 17, 2015
DOI:10.1021/acsami.5b09110
CeO2 rods with {110} facets and cubes with {100} facets were utilized as catalyst supports to probe the effect of crystallographic facets on the nickel species and the structure-dependent catalytic performance. Various analysis methods (ex and in situ XRD, TEM, Raman, XPS, TPR, TPD) were used to investigate the structural forms of the catalysts, and these results indicated that the deposition of nickel species resulted in the formation of two main active types of the catalyst components: NiO strongly or weakly interacted with the surface and Ni–Ce–O solid solution. Notably, the states and distribution ratio of nickel species were related to the shape of CeO2. It was found that CeO2 rods had more active sites to coordinate with nickel species to form a strong interaction with NiO on the surface and a more stable construction when compared to cubes. Furthermore, the nickel-ceria catalysts with rod shape were more active towards NO oxidation with complete conversion below 191 °C, but for cube shape, complete conversion occurred above 229 °C (e.g., for nickel loading of ∼5%, the complete conversion temperature was 154 °C for the rod shape and 229 °C for the cube shape). On the basis of the analysis of the catalysts structure, the superior catalytic activity was due to a combination of surface structures of NiO (mainly strongly interacting with the surface) and nickel ions Ni2+ in the Ni–Ce–O bulk phase.Keywords: crystallographic facets; multicomponent catalyst; nickel species; nickel-ceria catalyst; NO + CO reaction
Co-reporter:Yujuan Dong, Huiying Wei, Wei Liu, Qianjin Liu, Wenjing Zhang, Yanzhao Yang
Journal of Power Sources 2015 Volume 285() pp:538-542
Publication Date(Web):1 July 2015
DOI:10.1016/j.jpowsour.2015.03.078
•We used the template-free solvothermal method to synthesize V2O5 microspheres.•Microspheres was nanosheet-assembled.•Nanosheet-assembled microspheres exhibited higher specific capacity than nanorods.•Microspheres still kept a specific capacity of 200 mAh g−1 even at a rate of 5 C after 500 cycles.V2O5 microspheres with hierarchical structure via a facile two-step strategy. The first is preparing vanadium glycolate precursor through polyol medium template-free process and the second is subsequent thermal annealing treatment of the well-prepared precursors at high temperature in air. However, just by one-plot calcination of vanadium(IV) acetylacetone, V2O5 nanorods were obtained. The gained metal oxide were characterized by different physical and electrochemical analytical techniques. Electrochemical testing results show that V2O5 microspheres displayed a high specific discharge capacity of 275 mAh g−1 at 1 C which is higher than the obtained nanorods, and the microspheres still kept 243 mAh g−1 after 200 cycles. Notably, the nanosheet-assembled microspheres as electrode materials still show 200 mAh g−1 even at a rate of 5 C after 500 cycles. These results demonstrated that the well-prepared nanosheet-assembled microspheres are a fine cathode material for lithium ion battery with a high specific capacity and excellent cycle stability.
Co-reporter:Wei Liu, Tian Deng, Lijun Feng, Anran Xie, Jingcai Zhang, Shuping Wang, Xiufang Liu, Yanzhao Yang and Jinxin Guo
CrystEngComm 2015 vol. 17(Issue 26) pp:4850-4858
Publication Date(Web):21 May 2015
DOI:10.1039/C5CE00569H
In this work, a facile one-step solvothermal method with the assistance of hydrochloric acid has been developed to prepare well-dispersed CeO2 hollow nanospheres with high surface areas. The effects of hydrochloric acid on the growth mechanism and the size distribution are investigated in detail. It is found that the hydrogen ions expedite the nucleation rate of the CeO2 nuclei in the nucleation course, while the chloride ions accelerate the Ostwald ripening in the acidic environment. Both the hydrogen ion (H+) and the chloride ion (Cl−) are confirmed to play a key role in the formation of hollow morphology. Based on our experiments, a HCl-assisted oxidation–nucleation with an Ostwald ripening process mechanism was proposed. Furthermore, Au nanoparticles with a size of 2.5–6 nm were uniformly deposited on the surface of the ceria support by a simplified reduction process with sodium borohydride (NaBH4). The synthesized Au/CeO2 nanospheres exhibit a higher catalytic activity in CO oxidation than pure ceria nanospheres due to the existence of different Au species (metallic Au0 and positively charged Auδ+) and the strengthened interfacial interactions between the Au NPs and the ceria support.
Co-reporter:Ke Tang, Jingcai Zhang, Wenzhi Wang, Shuping Wang, Jinxin Guo and Yanzhao Yang
CrystEngComm 2015 vol. 17(Issue 13) pp:2690-2697
Publication Date(Web):18 Feb 2015
DOI:10.1039/C5CE00051C
A simple protocol has been reported here to successfully perform a controllable conversion between Ce(OH)4 nanorods [Ce(OH)4-NR] and Ce(OH)4 nanoflowers [Ce(OH)4-NF] based on a prolonged mechanical force-driven stirring process. Results show that the Ce(OH)4 nanostructures undergo a morphology transformation from the initial nanorods to irregular nanoflowers, then to nanoflowers emanating from one center only, by varying the stirring time before solvothermal reaction. The detailed study confirmed that the mechanical force significantly improved the mass transport of the solution and drove the seeds of Ce(OH)4-NR [seeds-NR] to generate the seeds of Ce(OH)4-NF [seeds-NF]. The final CeO2 products (CeO2 nanorods [CeO2-NR] and CeO2 nanoflowers [CeO2-NF]) that inherited the original morphology were obtained by annealing Ce(OH)4-NR and Ce(OH)4-NF, respectively. To further optimize the performance of the final products, Au/CeO2-NR and Au/CeO2-NF were synthesized by a simple oxidation–reduction process, which led to increased surface areas and promising potential in CO oxidation.
Co-reporter:Chen Wang, Yu Tong, Yixian Huang, Hong Zhang and Yanzhao Yang
RSC Advances 2015 vol. 5(Issue 77) pp:63087-63094
Publication Date(Web):02 Jul 2015
DOI:10.1039/C5RA06334E
A selenium-bearing extractant was evaluated for palladium extraction for the first time. The 1-butyl-3-methyl-imidazole-2-selone was synthesized, and dissolved in hydrophobic ionic liquids to extract palladium from aqueous solutions. Based on the studies of the influencing factors, the first elaboration of the selone extraction mechanism is offered. One of the Pd–selone complexes was analyzed with single crystal X-ray diffraction to explain the elevation of extractability relative to thiones from the molecular level. A novel combination of UV-vis spectroscopy, HPLC and 77Se{1H} NMR was first used to characterize the extraction system and to determine the complexing number. It was confirmed that various kinds of complexes had been extracted to the organic phase at different selone concentrations, thus the apparent complexing number was proposed to describe the extraction system. Both the extractability and the selectivity of the selone for Pd(II) extraction over other metal ions were evaluated to be high.
Co-reporter:Yixian Huang, Yu Tong, Chen Wang, Ke Tang and Yanzhao Yang
RSC Advances 2015 vol. 5(Issue 81) pp:66376-66383
Publication Date(Web):21 Jul 2015
DOI:10.1039/C5RA09166G
A group of new asymmetric branched alkyl sulfoxides was synthesized and applied in palladium(II) extraction for the first time. According to the experimental data, the concentration of hydrochloric acid in aqueous phase greatly influenced Pd(II) extraction, which could be interpreted by different mechanisms (ligand substitution mechanism at low acidity and ion association mechanism at high acidity). In regard to structure effect, the steric hindrance of branched alkyl showed remarkable influence on the extraction performance of sulfoxides. On the basis of thermodynamic analysis, it was demonstrated that higher temperature exerted positive influence on the Pd(II) extraction reaction. As for the separation of Pd(II) and Pt(IV), low concentration of hydrochloric acid was considered to be appropriate for highly effective separation. Furthermore, ammonia solution was proven to be an efficient stripping agent for palladium recovery from organic phase.
Co-reporter:Xiaoran Niu, Huiying Wei, Ke Tang, Wei Liu, Genyuan Zhao and Yanzhao Yang
RSC Advances 2015 vol. 5(Issue 81) pp:66271-66277
Publication Date(Web):30 Jul 2015
DOI:10.1039/C5RA14618F
In this paper, cation modified one dimensional Mn2O3 nanowires were synthesized via a solvothermal synthesis and calcination free from the template-assisted method. The samples were characterized in detail by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS). XRD results revealed the homogeneity of Ni–Mn–O/Co–Mn–O solid solutions. By introducing the two different cations the Mn2O3 nanowires can be freely manipulated. The H2-TPR measurement showed the enhanced reduction behaviors of the doped manganese oxide (Mn2O3) samples. The presence of Ni2+ and Co2+ produced lattice defects and promoted the production of oxygen vacancies, which explained the results that Ni2+/Co2+ doped Mn2O3 showed higher catalytic activity than the pure sample.
Co-reporter:Jingcai Zhang;Jinxin Guo;Wei Liu;Shuping Wang;Anran Xie;Xiufang Liu;Jun Wang
European Journal of Inorganic Chemistry 2015 Volume 2015( Issue 6) pp:969-976
Publication Date(Web):
DOI:10.1002/ejic.201403078
Abstract
A series of transition-metal-doped (Cu, Co, Ni, Mn) hierarchically mesoporous CeO2 nanoparticles have been fabricated through a simple solvothermal strategy. The effect of these doping metals on the morphology and the phase transformation of the Ce(HCOO)3 precursor was investigated. The specific order in which the doping metal cations (except Cu2+) are added during the synthesis process has a remarkable influence on the precursor morphology. By introducing these different metal cations, the doping composition can be adjusted freely. The XRD, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) results show the high homogeneity of the doped ceria and demonstrate that the transition metal cations have been incorporated into the CeO2 lattice. All of the doped ceria nanoparticles, especially the Cu2+-doped ceria product, exhibit improved reduction behavior and enhanced CO conversion performance.
Co-reporter:Jingcai Zhang;Jinxin Guo;Wei Liu;Shuping Wang;Anran Xie;Ke Tang
European Journal of Inorganic Chemistry 2015 Volume 2015( Issue 31) pp:5209-5217
Publication Date(Web):
DOI:10.1002/ejic.201500714
Abstract
Mesoporous CeO2 with flowerlike and cottonlike hierarchical structures were prepared through a facile solvothermal strategy by using cerium glycolate as precursors. In the whole synthesis process, the solvothermal reaction time plays an important role in morphology control. Structure and composition information of the corresponding cerium glycolate were obtained and compared by using X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Oriented attachment/anisotropic crystal growth with Ostwald ripening/multistep splitting process mechanism was proposed for the formation of the cerium glycolate precursor. The catalytic test results show that the final CeO2 microparticles exhibit enhanced CO conversion performance and better reduction behavior than pure ceria. Furthermore, as a good support, the synthesized Au/CeO2 samples demonstrate higher catalytic activity in the oxidation of CO than pure ceria.
Co-reporter:Xiaoran Niu, Huiying Wei, Wei Liu, Shuping Wang, Jingcai Zhang and Yanzhao Yang
RSC Advances 2015 vol. 5(Issue 42) pp:33615-33622
Publication Date(Web):25 Mar 2015
DOI:10.1039/C5RA04708K
In this study, a series of cobalt-doped MnCO3 hierarchical microstructures with different morphologies were synthesized by tuning a single variable (the dopant content) via a one-step, mild solvothermal synthesis in a N,N-dimethylformamide (DMF) solution system. Structure evolution of the polymorphic MnCO3 took place with the morphology obviously transforming from an initial flower-microstructure to fan-like, then to hedgehog-like hemispheres and finally to flake-spheres as the Co2+ theoretical content (Co/(Co + Mn)) increased from 0 to 20% in the solvothermal process. Cobalt ion modulated reaction-limited aggregation (RLA) is proposed in the growth mechanism. The mechanism of Co2+-induced acceleration and full growth is further investigated. The Co2+ doped manganese carbonate displays wonderful catalytic performance towards CO oxidation.
Co-reporter:Wei Liu, Xiufang Liu, Lijun Feng, Jinxin Guo, Anran Xie, Shuping Wang, Jingcai Zhang and Yanzhao Yang
Nanoscale 2014 vol. 6(Issue 18) pp:10693-10700
Publication Date(Web):09 Jul 2014
DOI:10.1039/C4NR02485K
In this paper, copper-doped ceria oxides with different hollowness and size are fabricated by changing the Cu2+ doping concentration in the mixed water-glycol system. Results show that the copper-doped CeO2 oxides undergo a morphology transformation from the solid nanospheres to core–shell, then to hollow nanospheres with the increase of the Cu2+ doping concentration. The corresponding size becomes smaller during this transfer process. The Cu2+ doping induced acceleration in the nucleation and growth process is further investigated. The resultant Cu2+-doped CeO2 oxides exhibit enhanced CO conversion performance and better reduction behaviors.
Co-reporter:Jingcai Zhang, Hongxiao Yang, Shuping Wang, Wei Liu, Xiufang Liu, Jinxin Guo and Yanzhao Yang
CrystEngComm 2014 vol. 16(Issue 37) pp:8777-8785
Publication Date(Web):29 Jul 2014
DOI:10.1039/C4CE01219D
In this paper, novel hierarchically mesoporous CeO2 nanoparticles assembled by hollow nanocones were prepared through a facile solvothermal strategy using Ce(HCOO)3 as the precursor. X-Ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM) and thermal gravimetric analysis (TGA) were utilized to characterize the products and research the formation mechanism. The whole synthesis process involves two steps: formation of Ce(HCOO)3 nanoparticles constructed with nanocones at room temperature in an alkaline environment and oxidation induced phase transformation from Ce(HCOO)3 to CeO2 with formation of hollow nanocones assembled by nanocrystals in a solvothermal process at 150 °C. The as-prepared mesoporous CeO2 nanoparticles with an average diameter of 500 nm displayed a high surface area of 147.6 m2 g−1 using N2 adsorption and desorption measurement. The H2-TPR test showed its great reduction behavior in a low temperature zone. By comparing the T100 temperature of CO conversion with a commercial sample (above 350 °C) and other reported samples (above 300 °C) in the literature, the mesoporous CeO2 nanoparticles (270 °C) presented an excellent catalytic activity for CO oxidation.
Co-reporter:Xiufang Liu;Lu Han;Wei Liu
European Journal of Inorganic Chemistry 2014 Volume 2014( Issue 31) pp:5370-5377
Publication Date(Web):
DOI:10.1002/ejic.201402570
Abstract
In this paper, pure ceria, ceria doped with transition metal ions (Co2+, Ni2+), and Co/Ni binary-doped ceria mesoporous notched hollow nanospheres were prepared from a one-step solvothermal synthesis. By introducing metal ions, the composition can be freely manipulated. The morphologies and crystalline structures of the products were characterized in detail by XRD, TEM, SEM, and HRTEM. The surface compositions of the as-prepared ceria samples were detected by Raman spectroscopy, energy-dispersive X-ray spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS). The surface areas and pore-size distributions of the as-obtained doped ceria mesoporous nanospheres were investigated by N2 adsorption–desorption measurements. Temperature-programmed reduction measurements under H2 (H2-TPR) showed the better reduction behavior of the doped ceria samples. Preliminary CO catalytic oxidation experiments indicated that the doped ceria samples showed strikingly higher catalytic activity, owing to the intrinsic surface defects of the samples. In addition, the as-obtained ceria nanospheres can be used as excellent supports for gold nanoparticles to remove CO by catalytic oxidation; therefore, they demonstrate a promising potential in environmental remediation. This one-step synthesis is a versatile approach and it could be extended to other binary or ternary metal oxide systems.
Co-reporter:Chen Wang, Wenjuan Lu, Yu Tong, Yan Zheng and Yanzhao Yang
RSC Advances 2014 vol. 4(Issue 100) pp:57009-57015
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4RA07563C
In view of the recycling and the preconcentration of palladium (Pd) from aqueous solutions, a sulfur-bearing extractant, 1,3-diethyl-imidazole-2-thione, in an ionic liquid organic phase was evaluated for palladium extraction. The extraction conditions were examined followed by mechanism studies. The aqueous Pd(II) was extracted using a neutral extraction mechanism, which can avoid or decrease the loss of ionic liquid used in traditional methods and highlight the green credentials of the ionic liquids. The extraction system also provides a new method for the preparation of metal complexes crystals. Investigations of the extracted complexes of palladium(II) with the EEImT ligand were conducted using single crystal X-ray diffraction and computational methods. The results showed that the Pd(II)–EEImT complexes with both 1:1 and 1:2 stoichiometry can be produced during extraction, rather than simply one structure. The cis geometry of the Pd(EEImT)2Cl2 complex was more favorable than the trans geometry. This was further explained by computer calculations, which suggested that the cis configuration with a larger dipole was energetically more stable than the trans configuration.
Co-reporter:Anran Xie, Jinxin Guo, Wei Liu and Yanzhao Yang
RSC Advances 2014 vol. 4(Issue 22) pp:11357-11359
Publication Date(Web):06 Jan 2014
DOI:10.1039/C3RA46292G
Uniform CeO2 asymmetric core–shell nanospheres were easily synthesized via a mild template-free hydrothermal method. The results show that aggregated solid spheres transform into core–shell spheres through an Ostwald ripening process.
Co-reporter:Yu Tong, Hongxiao Yang, Yixian Huang and Yanzhao Yang
Analytical Methods 2014 vol. 6(Issue 11) pp:3758-3762
Publication Date(Web):24 Mar 2014
DOI:10.1039/C4AY00594E
The hypochromic effect of bromocresol green (BCG) resulted from long-chained imidazolium ionic liquids was investigated. The hypochromic effect may be caused by the formation of the neutral complex [Cnmim]2+[BCG]2−via electrostatic interaction and hydrophobic interaction. Based on the spectral characteristics, a new method for determination of long-chained imidazolium ionic liquids is developed. The proposed method can be performed using a UV-vis spectrophotometer, at the optimum λmin. Beer's law is obeyed in the concentration range of 0.004–0.04 mmol L−1 for [C14mim]Br and [C16mim]Cl, and the detection limits are 0.0011 and 0.00095 mmol L−1 for [C14mim]Br and [C16mim]Cl, respectively. Meanwhile, precision, accuracy and tolerance are also very good. The method is fast, economical and does not require organic solvents; it can be applied for determination of long-chained imidazolium ionic liquids.
Co-reporter:Xiufang Liu;Wei Liu;Xueying Zhang;Lu Han;Cong Zhang
Crystal Research and Technology 2014 Volume 49( Issue 6) pp:383-392
Publication Date(Web):
DOI:10.1002/crat.201400039
Zirconium-doped ceria hollow slightly-truncated nano-octahedrons (HTNOs) (Ce1-xZrxO2) were synthesized by a one-pot, facile hydrothermal method. The morphology and crystalline structure were characterized with powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and the high resolution transmission electron microscopy (HRTEM). The composition and chemical valence on the surface of the as-prepared Ce1-xZrxO2 powders were detected by X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometry (EDS). The surface area and pore size distribution of as-obtained Zr-doped ceria HTNOs were measured by N2 adsorption-desorption measurement. Mechanisms for the growth of Zr-doped ceria HTNOs are proposed as both oriented attachment and Ostwald ripening process and the formation of the hollow structure is strongly dependent on the addition of Zr4+ ions. Furthermore, the as-obtained Zr-doped ceria HTNOs revealed superior catalytic activity and thermal stability toward CO oxidation compared to pure ceria. It may provide a new path for the fabrication of inorganic hollow structures on introducing alien metal ions.
Co-reporter:Anran Xie, Wei Liu, Shuping Wang, Xiufang Liu, Jingcai Zhang, Yanzhao Yang
Materials Research Bulletin 2014 59() pp: 18-24
Publication Date(Web):
DOI:10.1016/j.materresbull.2014.06.020
Co-reporter:Jun Wang;Lu Han;Shuping Wang;Jingcai Zhang
Catalysis Letters 2014 Volume 144( Issue 9) pp:1602-1608
Publication Date(Web):2014 September
DOI:10.1007/s10562-014-1293-6
Mesoporous MgAl2O4 spinel (MAO), prepared via one-pot evaporation induced self-assembly strategy, was reported here as an acid–base bifunctionalization catalyst for the reaction for ethyl methyl carbonate from dimethyl carbonate and diethyl carbonate. The physical/chemical properties of MgAl2O4 were characterized by X-ray powder diffraction, N2 adsorption–desorption, temperature programmed desorption and Fourier transform infrared. The effects to the reaction by adjusting the catalyst amount and reaction time were tested. The transesterification induced by MAO is much faster, and meantime, the thermal stability of MAO is much higher. Moreover, the catalyst can be used directly after filtration without drying and reused for at least five times with only 1.2 % loss in catalytic activity.
Co-reporter:Wei Liu, Lijun Feng, Cong Zhang, Hongxiao Yang, Jinxin Guo, Xiufang Liu, Xueying Zhang and Yanzhao Yang
Journal of Materials Chemistry A 2013 vol. 1(Issue 23) pp:6942-6948
Publication Date(Web):04 Apr 2013
DOI:10.1039/C3TA10487G
In this paper, a simple one-step hydrothermal method has been developed to prepare three-dimensional CeO2 microflower structures via a cerium oxalate precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM) and thermal gravimetric (TG) analysis were utilized to characterize the products. Herein, unlike the conventional calcination of a cerium oxalate precursor, oxalic acid acted not only as a precipitator but also as a modifier of morphology with a defined amount of C2O42−, while hydrogen peroxide (H2O2) was introduced as an oxidant to make the full conversion from Ce2(C2O4)3·10H2O to CeO2 in the hydrothermal process with the preserved flowerlike morphology. The as-obtained CeO2 microflowers displayed a high surface area of 147.6 m2 g−1 and narrow pore size of 3.759 nm by N2 adsorption and desorption measurement, and the H2-TPR test showed its better reduction behavior. Furthermore, CeO2 microflowers with hierarchical structures presented a higher catalytic activity for CO oxidation.
Co-reporter:Shuping Wang, Hongxiao Yang, Lijun Feng, Simou Sun, Jinxin Guo, Yanzhao Yang, Huiying Wei
Journal of Power Sources 2013 Volume 233() pp:43-46
Publication Date(Web):1 July 2013
DOI:10.1016/j.jpowsour.2013.01.124
A one-step co-precipitation process with ethylene glycol in aqueous solution was carried out to provide a convenient and economic route for the synthesis of nanoscale LiFePO4/C composites with uniform carbon coating and excellent electrochemical performance. It can be easily scaled up for commercialization.Highlights► A one-step co-precipitation process with ethylene glycol was applied. ► We found out a convenient route to synthesize nanoscale LiFePO4/C composites. ► The composites with uniform carbon coating performed excellently in electrochemical test. ► This method can reduce cost and is expected to have efficient commercial application.
Co-reporter:Xiufang Liu, Hongxiao Yang, Lu Han, Wei Liu, Cong Zhang, Xueying Zhang, Shuping Wang and Yanzhao Yang
CrystEngComm 2013 vol. 15(Issue 38) pp:7769-7775
Publication Date(Web):31 Jul 2013
DOI:10.1039/C3CE40959G
Uniform-sized and monodisperse CeO2 mesoporous hollow nanospheres composed of ceria nanocrystals were synthesized via a template-free and surfactant-assisted benign hydrothermal route. On the basis of a time-dependent experiment, the precipitation–dissolution–renucleation–assembly and Ostwald ripening processes mechanism is proposed for the formation of the CeO2 mesoporous hollow spheres. Poly(vinyl-pyrrolidone) (PVP) was applied as a surfactant to facilitate the reassembly of the CeO2 nanoparticles and the formation of the mesoporous shell of the hollow nanospheres. By increasing the amount of PVP, the mesoporous shell of the hollow spheres could be fabricated and became more apparent. Meanwhile, altering the amounts of H2O2 could control the size of the primary nanocrystals via affecting the nucleation/growth process of them, which is another key factor in the formation of the hollow structure and the uniform, monodispersed nanoparticles. The catalytic test results show that the as-obtained CeO2 mesoporous hollow spheres exhibited desirable CO catalytic properties. The synthesized Au–CeO2 nanospheres demonstrate a higher catalytic activity in CO oxidation than pure ceria nanospheres.
Co-reporter:Cong Zhang, Lu Han, Wei Liu, Hongxiao Yang, Xueying Zhang, Xiufang Liu and Yanzhao Yang
CrystEngComm 2013 vol. 15(Issue 25) pp:5150-5155
Publication Date(Web):25 Apr 2013
DOI:10.1039/C3CE40156A
A facile hydrothermal method has been employed to fabricate monodisperse Mn2O3 nano-flowers and Mn3O4 nano-ellipsoids. The possible mechanism of crystal growth was suggested based on time-dependent experiments, and the role that H2O2 played in the determination and formation of products Mn2O3 and Mn3O4 was investigated. These MnOx nano-particles have been demonstrated to be catalytically stable and active for CO oxidation.
Co-reporter:Simou Sun, Xiulan Zhao, Hang Lu, Zhida Zhang, Jingjing Wei and Yanzhao Yang
CrystEngComm 2013 vol. 15(Issue 7) pp:1370-1376
Publication Date(Web):28 Nov 2012
DOI:10.1039/C2CE26651B
In this paper, a series of nanostructured CeO2 spheres with two different dopants, Co2+ and Ni2+, were synthesized by a one-step hydrothermal synthesis free from the template-assisted calcination, and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS) and nitrogen adsorption–desorption measurements. The formation process of the produced spheres involved Ostwald ripening, secondary nucleation and oriented attachment. Both the presence of Co2+, Ni2+ and the interaction of Ce4+/Ce3+ with dopants promoted the production of oxygen vacancies, which explained the result that the catalytic performance in CO oxidation of CeO2 with both dopants was better than that with single dopant, and that with single dopant held much advantage towards pure CeO2.
Co-reporter:Yanmin Lu;Wenjuan Lu;Wei Wang;Qingwei Guo
Journal of Chemical Technology and Biotechnology 2013 Volume 88( Issue 3) pp:415-421
Publication Date(Web):
DOI:10.1002/jctb.3868
Abstract
BACKGROUND: Aqueous two-phase extraction is a versatile method for separating biological particles and macromolecules. In the present wok, the feasibility of using PEG 4000/potassium citrate aqueous two-phase system (ATPS) for recovering and purifying lysozyme was investigated. Response surface methodology was used to determine an optimized ATPS for purification of lysozyme from crude hen egg white.
RESULTS: Mathematical models concerning the purification of lysozyme from chicken egg white in polyethylene glycol 4000 (PEG 4000)/potassium citrate ATPS are established using response surface methodology. Screening experiments using fractional factorial designs show that the pH of the system significantly affects the recovery and purification of lysozyme. An optimized ATPS was proved to be at pH 5.5 and 30 °C and contained 18% (w/w) PEG, 16% (w/w) potassium citrate, 3.75% (w/w) potassium chloride (KCl). Under those conditions, the specific activity, purification factor and activity yield for lysozyme were 31100 U mg−1, 21.11 and 103%, respectively.
CONCLUSION: The PEG 4000/potassium citrate ATPS has the potential to be applied to establish bioprocesses for the primary recovery and partial purification of lysozyme. © 2012 Society of Chemical Industry
Co-reporter:Xueying Zhang;Jingjing Wei;Hongxiao Yang;Xiufang Liu;Wei Liu;Cong Zhang
European Journal of Inorganic Chemistry 2013 Volume 2013( Issue 25) pp:4443-4449
Publication Date(Web):
DOI:10.1002/ejic.201300370
Abstract
Ceria nanoparticles with 4 and 7 atom-% manganese dopant were synthesized through a template-free solvothermal method. The structure of the samples was characterized by powder X-ray diffraction (XRD). Monodispersed nanospheres of average size 130 nm were observed in transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), and field-emission scanning electron microscopy (FE-SEM) analyses. Manganese ions were introduced into the system and it is confirmed that the Mn species dissolve within the CeO2 lattice by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Furthermore, the as-obtained Mn-doped ceria nanoparticles revealed superior catalytic performance in CO oxidation in contrast with pure CeO2 prepared by the same route.
Co-reporter:Ling Liu, Yanzhao Yang
Superlattices and Microstructures 2013 Volume 54() pp:26-38
Publication Date(Web):February 2013
DOI:10.1016/j.spmi.2012.11.004
A polyol-based precursor route was developed to synthesize MnCo complex oxide with well-defined morphologies, in which ethylene glycol (EG) was treated with metal acetates in the presence of poly(vinyl-pyrrolidone) (PVP). By varying the reaction temperature, the as-obtained precursor was readily regulated its morphologies, which could vary from nanospheres to hierarchically stacked nanoplates. The initial molar ratio of Mn-acetate to Co-acetate in EG solution played a crucial role in determining the chemical composition of the nano/microstructured precursor. On the basis of the experimental results, a possible growth mechanism for the nanostructured precursor was proposed. MnCo2O4 and CoMn2O4 could be obtained from their precursors without changing the morphologies by a simple calcination procedure. The synthetic methodology appears to be general and promises to provide an entryway into other complex oxide materials with various nano/microstructures. As an example of potential applications, the as-obtained MnCo mixed oxide nano/microstructures were used as catalyst in CO oxidation, and the effect of the morphology and composition on catalytic activities was investigated.Highlights► Nanostructured MnCo complex oxides were prepared by a polyol-based precursor route. ► The morphology of precursors was tunable by adjusting reaction temperatures. ► The morphology evolution was controlled by kinetically driven crystallization process. ► The composition of samples was tunable by adjusting the proportion of raw materials. ► CO catalytic oxidiate of the samples with different shapes and compositions was studied.
Co-reporter:Yu Tong, Hongxiao Yang, Jing Li, Yanzhao Yang
Separation and Purification Technology 2013 120() pp: 367-372
Publication Date(Web):
DOI:10.1016/j.seppur.2013.10.028
Co-reporter:Hongxiao Yang, Shuping Wang, Yanzhao Yang
Materials Letters 2013 110() pp: 45-48
Publication Date(Web):
DOI:10.1016/j.matlet.2013.07.094
Co-reporter:Hongxiao Yang, Shuping Wang and Yanzhao Yang
CrystEngComm 2012 vol. 14(Issue 3) pp:1135-1142
Publication Date(Web):21 Nov 2011
DOI:10.1039/C1CE06143G
Novel Zn-doped In2O3 nanocages and hollow spindle-like nanostructures (HSNs) have been prepared by calcining precursors obtained via a facile template-free hydrothermal method. The change in morphology, size, and phase compositions in a controlled synthesis of the Zn-doped In2O3 nanostructures are achieved by simple adjustments of the amount of water. The result of this formation mechanism investigation reveals that the amount of water and the reaction time make significant contributions to the growth of Zn-doped In2O3 nanostructures. The driving forces for the formation of the nanostructures are the precipitation–dissolution–renucleation–growth and Ostwald ripening processes based on time-dependent experimental results. The gas-sensing properties of Zn-doped In2O3 nanocages and HSNs have shown high sensitivity toward formaldehyde (HCHO) vapor at a relatively low operating temperature. Note that the gas sensor fabricated with Zn-doped In2O3 HSNs exhibit a higher and faster response than those fabricated with Zn-doped In2O3 nanocages due to the larger surface area and the decreasing size of the particle.
Co-reporter:Yu Tong, Lu Han, and Yanzhao Yang
Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 50) pp:16438
Publication Date(Web):November 24, 2012
DOI:10.1021/ie301644t
A microemulsion consisting of cyclohexane, n-hexanol, hydrochloric acid solution, and the ionic liquid 1-n-tetradecyl-3-methylimidazolium bromide ([C14mim]Br) was investigated for Au(III) extraction. In the extraction system, [C14mim]Br bears double functions of surfactant and extractant. The anion-exchange mechanism of Au(III) extraction by [C14mim]Br was confirmed by the method of continuous variation and infrared spectrum analysis. The effects of extraction time and various material concentrations were examined for Au(III) extraction. Under optimum conditions, almost all the Au(III) in hydrochloric acid solution was extracted to the microemulsion phase, which also has high selectivity for Au(III) over some metals (Cu(II), Cd(II), Co(II), Ni(II), Sb(III), Fe(III), Al(III), and Sn(IV)). Therefore, the extraction of Au(III) by the [C14mim]Br/cyclohexane/n-hexanol/HCl microemulsion is an efficient and effective approach with high selectivity.
Co-reporter:Lijun Feng, Shuping Wang, Lu Han, Xuyang Qin, Huiying Wei, Yanzhao Yang
Materials Letters 2012 Volume 78() pp:116-119
Publication Date(Web):1 July 2012
DOI:10.1016/j.matlet.2012.03.019
Spinel LiMn2O4 was synthesized by solid state reaction. 5.0 wt.% of La2O3 was coated on the surface of LiMn2O4 via ball-milling method, followed by calcination at 650 °C for 5 h in the air. The uncoated and La2O3-coated LiMn2O4 materials were physically characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area measurements. It was observed that Li/LiMn2O4 electrode obtained the capacity retention of 76.7% after 205 cycles at 1 C rate at 25 °C while that of the coated sample was 90.1%. At 55 °C, the bare and coated LiMn2O4 showed a capacity retention of 69.4% and 82.6% after 95 cycles, respectively. Rate capability was also improved. The capacity retention of uncoated and La2O3-coated materials reduced to 46.9% and 80.3% at 10 C-rate, respectively.Highlights► Nano-La2O3 (5.0 wt.%) coated LiMn2O4 has been synthesized via ball-milling method. ► TEM images indicate that La2O3 layer was formed over the bare LiMn2O4 powder. ► The La2O3-coated LiMn2O4 exhibited an excellent capacity retention. ► Rate capability of the La2O3-coated LiMn2O4 was also improved.
Co-reporter:Jingjing Wei, Shuping Wang, Simou Sun, Zhijie Yang, Yanzhao Yang
Materials Letters 2012 Volume 84() pp:77-80
Publication Date(Web):1 October 2012
DOI:10.1016/j.matlet.2012.06.077
Monodisperse CeO2 hollow nanoparticles were synthesized by a template-free hydrothermal method. The average size of the nanoparticles was measured to be 75 nm. Detailed experiments revealed that the CeO2 hollow nanoparticles were formed directly by oriented attachment of the initial CeO2 nanocrystals. Although Cu2+ was introduced into the system, the final CeO2 product was free of Cu species, which was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectrum (XPS) studies. Furthermore, the as-prepared CeO2 hollow nanoparticles revealed superior catalytic activity toward CO oxidation compared to commercial CeO2 fine powders. It may provide a new path for the fabrication of inorganic hollow structures upon introducing alien metal ions.Highlights► Hollow CeO2 nanoparticles were fabricated through a Cu2+-assisted hydrothermal route. ► The monodispersed CeO2 nanoparticles can form colloidal solution in water. ► The hollowing process can be attributed to the oriented attachment mechanism. ► CeO2 hollow nanoparticles show superior catalytic activity than commercial CeO2.
Co-reporter:K. Shang;Y. Z. Yang;J. X. Guo;W. J. Lu
Journal of Radioanalytical and Nuclear Chemistry 2012 Volume 291( Issue 3) pp:629-633
Publication Date(Web):2012 March
DOI:10.1007/s10967-011-1443-x
The extraction of cobalt by Winsor II microemulsion system was studied. In the bis (2-ethylhexyl) sulfosuccinate sodium salt (AOT)/n-pentanol/n-heptane/NaCl system, AOT was used as a anionic surfactant to form microemulsion in n-heptane, n-pentanol was injected in the microemulsion as a cosurfactant. Co(II) was found to be extracted into the microemulsion phase due to ion pair formation such as Co2+(R–SO3−)Cl. The influence of different parameters such as the volume ratio of aqueous phase to microemulsion, surfactant concentration, pH of the feed solutions, cosurfactant concentration as well as temperature on the extraction yield (E%) were investigated. The results showed that it was possible to extract 95% of cobalt by the AOT Winsor II microemulsion.
Co-reporter:Jingjing Wei, Zhijie Yang, Hongxiao Yang, Tao Sun and Yanzhao Yang
CrystEngComm 2011 vol. 13(Issue 15) pp:4950-4955
Publication Date(Web):08 Jun 2011
DOI:10.1039/C1CE05324H
In this paper, a facile and economical route based on an oxidation induced phase transformation in alcoholic solution was developed to prepare mesoporous CeO2 nanoflowers. The whole process could be divided into two steps: the formation of Ce(HCOO)3 with flower-like structures and the oxidation induced phase transformation from Ce(HCOO)3 to CeO2 with unchanged morphology in the alcoholic solution. TEM results revealed that the CeO2 nanoflowers consist of rods with length and diameter of 100 and 30 nm, respectively. N2 adsorption/desorption experiments indicated that the CeO2 nanoflowers display mesoporous structures with a mean pore size of 4 nm, and the BET surface area and pore volume of such flower-like structures are 95.7 m2 g−1 and 0.173 cm3 g−1, respectively. Prompted by the mesoporous structure, high surface area and high pore volume, we speculate that these mesoporous CeO2 flowers could be promising candidates for practical catalytic application.
Co-reporter:Hongxiao Yang, Ling Liu, Hui Liang, Jingjing Wei and Yanzhao Yang
CrystEngComm 2011 vol. 13(Issue 15) pp:5011-5016
Publication Date(Web):10 Jun 2011
DOI:10.1039/C1CE05274H
Phase-pure porous nanospheres, both In(OH)3 and InOOH, have been prepared through a facile hydrothermal method using different organic acids as the assistant agents. The organic acids play an important role in the phase change, and the phase composition of the precursors could be deliberately controlled by adjusting the organic acid (citric acid or tartaric acid). Cubic and hexagonal In2O3 monodispersed nanospheres with porosity can be obtained from In(OH)3 and InOOH, respectively, while size and morphology can be maintained to a certain extent. The as-synthesized porous In2O3 nanospheres are composed of numerous small nanocrystallites and possess good size uniformity. Influencing factors such as the reaction time and the type and amount of organic acids were systematically investigated. A possible ethylenediamine or tartaric acid coordinated mechanism of the phase-control synthesis of In2O3 was proposed based on the experimental results. Furthermore, the potentialities of the porous In2O3 nanospheres were also studied by room-temperature photoluminescence (PL) spectroscopy.
Co-reporter:Hui Liang, Ling Liu, Hongxiao Yang, Jingjing Wei, Zhijie Yang and Yanzhao Yang
CrystEngComm 2011 vol. 13(Issue 7) pp:2445-2450
Publication Date(Web):01 Feb 2011
DOI:10.1039/C0CE00594K
Large-scale uniform γ-AlOOH micro/nanoarchitectures (ellipsoidal flower-like, rotor-like, carambola-like and leaf-like) were synthesized through a facile one-step solution phase route. The products were examined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Influencing factors such as the volume ratio of DMF to water, the content of AlCl3, reaction temperature and reaction time were systematically investigated. A possible formation mechanism of the novel γ-AlOOH micro/nanostructures was proposed based on the experimental results. The room-temperature photoluminescence (PL) spectra of the obtained γ-AlOOH structures were also studied and the results indicate that the luminescence properties of the products are dependent on their morphologies.
Co-reporter:Jingjing Wei, Zhijie Yang and Yanzhao Yang
CrystEngComm 2011 vol. 13(Issue 7) pp:2418-2424
Publication Date(Web):01 Feb 2011
DOI:10.1039/C0CE00635A
In this paper, three dimensional mesoporous CeO2 hierarchical structures were synthesized through the thermal decomposition of cerium formate precursors, which were prepared by a solvothermal method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR), and Thermal gravimetric (TG) was applied to characterize the precursors. Urchin-like Ce(HCOO)3 precursors were prepared using dimethyl sulfoxide (DMSO) and ammonia solution (1 M) as solvent and base source, respectively, while coral-like Ce(HCOO)3 precursors were prepared using dimethyl formamide (DMF) and NH4HCO3 as solvent and base source, respectively. The formation mechanism of the hierarchical structured precursors was proposed involving a process of anisotropic growth–H2O induced self-assembly–oriented aggregation and disassembly–Ostwald ripening. CeO2 hierarchical structures were obtained by annealing the corresponding Ce(HCOO)3 precursors at 400 °C for 60 min. N2 adsorption–desorption isotherms indicate that both CeO2 hierarchical structures derived from their Ce(HCOO)3 precursors display large surface areas and high pore volumes. In addition, the as-prepared CeO2 catalysts with hierarchical structures are highly active for conversion of CO to CO2.
Co-reporter:Zhijie Yang;Jingjing Wei;Hongxiao Yang;Ling Liu;Hui Liang
European Journal of Inorganic Chemistry 2011 Volume 2011( Issue 12) pp:
Publication Date(Web):
DOI:10.1002/ejic.201100214
No abstract is available for this article.
Co-reporter:Ling Liu, Hongxiao Yang, Jingjing Wei, Yanzhao Yang
Materials Letters 2011 Volume 65(Issue 4) pp:694-697
Publication Date(Web):28 February 2011
DOI:10.1016/j.matlet.2010.11.042
A facile one-step solvothermal route was developed to synthesize monodisperse Mn3O4 and Mn2O3 nanostructures with the introduction of poly(vinyl-pyrrolidone)/stearic acid (PVP/SA) mixture. H2O2 played a key role in the determination of the products Mn3O4 and Mn2O3. The synthesis parameters for nanostructured MnOx such as surfactant and reaction time were investigated, along with their influences on morphology and composition. The morphology evolution of the Mn3O4 and Mn2O3 reveals that the nanostructures formed via two distinct mechanisms of nucleation and growth of nanocrystals.
Co-reporter:Jingjing Wei;Zhijie Yang;Huiying Wei
Crystal Research and Technology 2011 Volume 46( Issue 2) pp:201-204
Publication Date(Web):
DOI:10.1002/crat.201000479
Abstract
Monodisperse CeO2 spherical aggregates with diameters ranging from 200 to 300 nm have been successfully synthesized through a facile hydrothermal method. The structure and morphology of the samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and field-emission scanning electron microscopy (FE-SEM). The building blocks (primary nanocrystals) of the spherical aggregates could be effectively tuned by adding different amount of urea. Furthermore, N2 adsorption/desorption experiment displays a gradual increase of BET surface areas of spherical aggregates with increasing the amount of urea. Finally, the formation mechanism of CeO2 spherical aggregates was preliminarily discussed. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Co-reporter:Yanmin Lu, Wenjuan Lu, Wei Wang, Qingwei Guo, Yanzhao Yang
Talanta 2011 Volume 85(Issue 3) pp:1621-1626
Publication Date(Web):15 September 2011
DOI:10.1016/j.talanta.2011.06.058
The ionic liquid/aqueous two-phase extraction systems (ATPSs) based on imidazolium ionic liquids were used to extract cytochrome c. Effects of the alkyl chain length of the ionic liquid cations, concentration of potassium citrate, temperature and pH on the extraction efficiency have been investigated. The thermodynamic parameters (ΔGT°, ΔHT° and ΔST°) associated with Cyt-c partitioning in aqueous two phase systems were determined. Thermodynamic studies indicated that the partitioning of Cyt-c was driven by both hydrophobic and electrostatic interactions in the extraction process. Under the optimum conditions, experiment results showed that 94% of the cytochrome c could be extracted into the ionic liquid-rich phase in a one-step extraction. The structural characterization of Cyt-c in the IL ATPS was investigated by UV–vis and circular dichroism (CD) spectra. The results demonstrated that no direct bonding interaction observed between ionic liquid and cytochrome c, while the native properties of the cytochrome c were not altered. Compared with traditional liquid–liquid extractions based on toxic organic solvents, ionic liquid/aqueous two phase extraction offers clear advantages due to no use of volatile organic solvent and low consumption of imidazolium ionic liquids.
Co-reporter:Qingchi Sun;Yanmin Lu;Wenjuan Lu
Applied Biochemistry and Biotechnology 2011 Volume 163( Issue 6) pp:744-755
Publication Date(Web):2011 March
DOI:10.1007/s12010-010-9079-9
The extraction of bovine serum albumin (BSA) has been investigated using reverse micelles of hexadecyl trimethyl ammonium chloride/n-octanol/isooctane. Forward extraction process parameters such as the surfactant concentration, co-solvent concentration, pH, ionic strength, and species of the initial aqueous phase were important factors affecting the extraction performance. These parameters were varied to optimize the extraction efficiency. Under the optimized conditions, forward extraction efficiencies of BSA can reach practically 99.55%. The thermodynamic study revealed that the extraction of BSA is controlled by entropy changes. Maximum back-extraction efficiency of 85.16% can be obtained at low pH values and high salt concentrations. The structures of BSA during reverse micelle extraction did not change by comparing the circular dichroism spectra of BSA back-extracted to the aqueous phase with that of feed BSA.
Co-reporter:Zhijie Yang, Dongqing Han, Donglin Ma, Hui Liang, Ling Liu and Yanzhao Yang
Crystal Growth & Design 2010 Volume 10(Issue 1) pp:291-295
Publication Date(Web):October 27, 2009
DOI:10.1021/cg900898r
A simple hydrothermal method has been employed to fabricate monodisperse CeO2 hollow spheres assembled by nano-octahedra. Results revealed that the as-obtained CeO2 hollow spheres were assembled by nano-octahedra with an average edge length of ca. 20 nm. A possible crystal growth and hollowing mechanism was suggested based on the detailed experiment. The CO oxidation properties were investigated, and the novel structured CeO2 hollow spheres exhibited a higher catalytic properties compared to the commercial CeO2 powders.
Co-reporter:Zhijie Yang;Jingjing Wei;Hongxiao Yang;Ling Liu;Hui Liang
European Journal of Inorganic Chemistry 2010 Volume 2010( Issue 21) pp:3354-3359
Publication Date(Web):
DOI:10.1002/ejic.201000030
Abstract
CeO2 hollow spheres (250–350 nm in diameter), with mesoporous shells of approximately 50 nm, were synthesized by a one-pot, template-free hydrothermal method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and nitrogen adsorption–desorption measurements were used to characterize the products. The formation of these hollow spheres involves the aggregation of the initial nanoparticles followed by solid evacuation driven by an Ostwald ripening process. The mesoporous CeO2 hollow spheres showed an excellent adsorption capacity for organic pollutants (Congo red) from waste water (about 84 mg Congo red per g CeO2). Furthermore, relative to commercial CeO2 powders, the CeO2 hollow spheres exhibited a higher catalytic activity towards CO oxidation.
Co-reporter:Fei Liu, Yanzhao Yang, Yanmin Lu, Kai Shang, Wenjuan Lu, and Xidan Zhao
Industrial & Engineering Chemistry Research 2010 Volume 49(Issue 20) pp:10005
Publication Date(Web):September 28, 2010
DOI:10.1021/ie100963t
The extraction of germanium to a W/O microemulsion by the combination with an anionic surfactant and an amine extractant was studied. In the AOT/n-butanol/n-heptane/Na2SO4/N235 system, AOT was used as an anionic surfactant to form a microemulsion in n-heptane, n-butanol was injected in the microemulsion as a cosurfactant to enhance the stability, and N235 was a typical extractant in the system. The microemulsion system without N235 showed poor extractability and stability. However, by adding N235, the extraction efficiency (E%) can be more than 99%, and the stability of the microemulsion extremely enhanced. The influences of the concentration of cosurfactant, temperature, pH of the feed solution, and composition of the feed solution on the extraction efficiency (E%) were verified.
Co-reporter:Ling Liu, Zhijie Yang, Hui Liang, Hongxiao Yang, Yanzhao Yang
Materials Letters 2010 Volume 64(Issue 7) pp:891-893
Publication Date(Web):15 April 2010
DOI:10.1016/j.matlet.2010.01.054
Manganese oxide nanoplates with different shapes have been prepared based on an ethylene glycol-mediated route. The first step consists of precipitating manganese alkoxide precursor in a polyol process from the reaction of manganese acetate with ethylene glycol. During this process, the morphologies of the prepared precursor could be tuned from disc-shaped to hexagonal nanoplates by introducing different organic additives. The second step involves the treatment of the precursor under different conditions. Crystalline Mn2O3 with the same morphology was readily obtained by calcination of the manganese alkoxide precursor. Furthermore, Mn3O4 nanoplates could be obtained by immersing the precursor into the deionized water.
Co-reporter:Ling Liu, Zhijie Yang, Hui Liang, Hongxiao Yang, Yanzhao Yang
Materials Letters 2010 Volume 64(Issue 19) pp:2060-2063
Publication Date(Web):15 October 2010
DOI:10.1016/j.matlet.2010.06.037
Manganese carbonate (MnCO3) hollow dumbbells were synthesized via a polyol process. Based on the structural analysis of the samples obtained at different reaction times, a mechanism of nucleation-growth-aggregation-ripening was proposed to account for the formation of the hollow dumbbells. Moreover, the manganese oxide has also been obtained from the MnCO3 crystals after thermal transformation in laboratory air, and the phase of final product could easily be controlled to be either MnO2 or Mn2O3, simply by altering the calcination conditions. The manganese oxide powder products possessed mesoporosity and essentially preserved the pristine morphology of the MnCO3 precursor.
Co-reporter:Hongxiao Yang, Zhijie Yang, Hui Liang, Ling Liu, Jinxin Guo, Yanzhao Yang
Materials Letters 2010 Volume 64(Issue 13) pp:1418-1420
Publication Date(Web):15 July 2010
DOI:10.1016/j.matlet.2010.03.030
In this work, we demonstrate that monodisperse indium hydroxide (In(OH)3) nanorods constructed with parallel wire-like subunits have been fabricated via a acrylamide-assisted synthesis route without any template. NH3 from the hydrolysis of acrylamide acts as the OH− provider. The structure and morphology of as-prepared products have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis (TG). A detailed mechanism has been proposed on the basis of time-dependent experimental results. Furthermore, by annealing In(OH)3 precursors at 500 °C for 3 h in air, In2O3 samples were obtained with the designed morphology.
Co-reporter:Hui Liang, Hongxiao Yang, Ling Liu, Zhijie Yang, Yanzhao Yang
Superlattices and Microstructures 2010 Volume 48(Issue 6) pp:569-576
Publication Date(Web):December 2010
DOI:10.1016/j.spmi.2010.09.007
The porous αα- Ni(OH)2 microflowers were successfully prepared by a facile solvothermal method without the utility of templates and additives. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TG) and nitrogen adsorption–desorption measurement. The obtained αα- Ni(OH)2 products exhibited a flowerlike structure composed of porous petals with diameters of 1–3 μm. The novel nucleation-rapid aggregation–dissolution–recrystallization formation mechanism was proposed based on the experimental results. The αα- Ni(OH)2 microflowers displayed large Brunauer–Emmett–Teller (BET) surface area of 252.4 m2/g. Furthermore, by annealing αα- Ni(OH)2 precursors at 300 °C for 3 h in air, NiO was obtained with the designed morphology.
Co-reporter:Hui Liang;Ling Liu;Zhijie Yang
Crystal Research and Technology 2010 Volume 45( Issue 2) pp:195-198
Publication Date(Web):
DOI:10.1002/crat.200900514
Abstract
Uniform γ-AlOOH architectures assembled by nanosheets were successfully synthesized in the mixture of deinonized water and dimethyl sulfoxide (DMSO) at 180 °C. The structure and morphology of products were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The products displayed 3D microstructures with its length of 1 μm and diameter of 400-500 nm. The obtained γ-AlOOH structures exhibited large Brunauer-Emmett-Teller (BET) surface area of 216.5 m2/g and pore size of 3.7 nm. The formation mechanism of 3D γ-AlOOH architectures was also discussed based on the experimental results. Furthermore, the γ-AlOOH architectures exhibited preliminary photoluminescence (PL) phenomenon with a strong peak at 323 nm. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Co-reporter:Hui Liang;Ling Liu;Zhijie Yang
Crystal Research and Technology 2010 Volume 45( Issue 6) pp:661-666
Publication Date(Web):
DOI:10.1002/crat.200900732
Abstract
Ultralong α-Ni(OH)2 nanobelts with uniform size have been prepared on large scale via a facile template-free hydrothermal method. The as-prepared nanobelts were single crystals, with several tens of microns in length and about 100 nm in width. For the whole process, a novel nucleation–aggregation–dissolution–seed-directed growth mechanism was proposed based on the experimental results. The roles of aqueous ammonia and hydrothermal temperature were also discussed. Furthermore, porous NiO nanobelts were obtained by annealing the as-prepared Ni(OH)2 nanobelts. This facile, template-free, and low cost method might feasibly be scaled up for industrial production. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Co-reporter:Zhijie Yang, Yanzhao Yang, Hui Liang, Ling Liu
Materials Letters 2009 Volume 63(Issue 21) pp:1774-1777
Publication Date(Web):31 August 2009
DOI:10.1016/j.matlet.2009.05.034
Monodisperse CeO2 nanocubes have been fabricated via an acrylamide-assisted hydrothermal route. NH3 and acrylic acid from the hydrolysis of acrylamide act as OH− provider and capping reagent, respectively. The structure and morphology of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM) and Fourier transformed infrared (FT-IR). The products have a cubic morphology with a mean size of 200 nm. The possible formation mechanism has been discussed based on the experimental results.
Co-reporter:Yan-Zhao Yang, Tao Zhu, Chuan-Bo Xia, Xue-Mei Xin, Ling Liu, Zhan-Yu Liu
Separation and Purification Technology 2008 Volume 60(Issue 2) pp:174-179
Publication Date(Web):20 April 2008
DOI:10.1016/j.seppur.2007.08.006
The influences of the concentration of cosurfactant and surfactant on the water content of the microemulsion were studied, and the proper microemulsion extraction system has been obtained. Secondly, the effects of the concentration of CTMAB, pentanol, ammonium thiocyanate, sodium thiocyanate; and also the volume ratio of aqueous to microemulsion (R) and temperature on the extraction yield (E%) were investigated, the mechanism of the cobalt extraction was discussed. The extraction yield (E%) of nickel was much lower than cobalt, which make the separation of cobalt and nickel possible. In the stripping stage, the metals extracted in the microemulsion phase were precipitated by Na2CO3 solution and the microemulsions were recycled for further use.
Co-reporter:Chuan-Bo Xia;Yan-Zhao Yang;Xue-Mei Xin
Journal of Radioanalytical and Nuclear Chemistry 2008 Volume 275( Issue 3) pp:535-540
Publication Date(Web):2008 March
DOI:10.1007/s10967-007-6960-2
The influence of the concentration of sodium oleate (NaOL), alcohol and the nature of the internal water phase on the water content of microemulsion was studied. The effect of the concentration of NaOL, sodium stearate, alcohol, salting-out agent, Alamine 336 added and of the contact time, volume ratio of the aqueous to microemulsion (R) and temperature on the extraction yield of samarium was investigated. The result shows that the extraction of samarium is effective under well-defined conditions utilizing WinsorII microemulsion systems.
Co-reporter:Zhijie Yang, Ling Liu, Hui Liang, Hongxiao Yang, Yanzhao Yang
Journal of Crystal Growth (15 January 2010) Volume 312(Issue 3) pp:426-430
Publication Date(Web):15 January 2010
DOI:10.1016/j.jcrysgro.2009.11.027
In this work, we report a simple one-pot hydrothermal approach to prepare CeO2 hollow microspheres with a mean diameter of 1.5 μm and a shell thickness of 90 nm. Structure and morphology of CeO2 hollow spheres were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), field-emission scanning electron microscope (FE-SEM), and N2 adsorption–desorption. In the reaction system, l-asparagine and KBrO3 act as OH− provider and oxidizer, respectively. Reaction duration and l-asparagine content are shown to play important roles in the formation of the hollow structures. A hollowing mechanism is proposed based on the experimental results.
Co-reporter:Zhaohua Song, Xia Xin, Jinglin Shen, Han Zhang, Shubin Wang and Yanzhao Yang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 36) pp:NaN8447-8447
Publication Date(Web):2016/08/08
DOI:10.1039/C6TC02329K
The hierarchical self-assembly of a biological surfactant, sodium deoxycholate (NaDC), and a cationic dye (RhB) through ionic self-assembly (ISA) opens up potentially useful routes to construct soft materials. Our results have shown that different morphologies with high hierarchies can be reversibly controlled by varying the ratio of the two components (NaDC and RhB) and that the morphologies can switch between porous microspheres and urchin-like structures. It can be concluded that the interaction between NaDC and RhB was strongly influenced by direct electrostatic forces between the –COO− groups in NaDC and –N+ in RhB, respectively. Moreover, because of the novel nanostructures, they have functional applications for photoluminescence enhancement and hydrophobicity. Thus, it can be expected that this ISA strategy can be used towards the development of new protocols for the fabrication of novel materials, which are potentially biocompatible and biodegradable and gives new insight into the main (soft-interactions) self-assembly processes.
Co-reporter:Wenhui Liu, Qi Wang, Yan Zheng, Shubin Wang, Yan Yan and Yanzhao Yang
Dalton Transactions 2017 - vol. 46(Issue 22) pp:NaN7218-7218
Publication Date(Web):2017/05/02
DOI:10.1039/C7DT01142C
In this study, a method of one-step separation and recycling of high purity Pd(II) and Pt(IV) using an ionic liquid, 1-butyl-3-benzimidazolium bromate ([HBBIm]Br), was investigated. The effects of [HBBIm]Br concentration, initial metal concentration, and loading capacity of [HBBIm]Br were examined in detail. It was observed that [HBBIm]Br was a very effective extractant for selectively extracting Pd(II) and precipitating Pt(IV). Through selectively extracting Pd(II) and precipitating Pt(IV), each metal with high purity was separately obtained from mixed Pd(II) and Pt(IV) multi-metal solution. The method of one-step separation of Pd(II) and Pt(IV) is simple and convenient. The anion exchange mechanism between [HBBIm]Br and Pt(IV) was proven through Job's method and FTIR and 1H NMR spectroscopies. The coordination mechanism between [HBBIm]Br and Pd(II) was demonstrated via single X-ray diffraction and was found to be robust and distinct, as supported by the ab initio quantum-chemical studies. The crystals of the [PdBr2 ·2BBIm] complex were formed first. Moreover, the influence of the concentrations of hydrochloric acid, sodium chloride, and sodium nitrate on the precipitation of Pt(IV) and extraction of Pd(II) was studied herein. It was found that only the concentration of H+ could inhibit the separation of Pt(IV) because H+ could attract the anion PtCl62−; thus, the exchange (anion exchange mechanism) between the anions PtCl62− and Br− was prevented. However, both the concentration of H+ and Cl− can obviously inhibit the extraction of Pd(II) because H+ and Cl− are the reaction products and increasing their concentration can inhibit the progress of the reaction (coordination mechanism).
Co-reporter:Wei Liu, Lijun Feng, Cong Zhang, Hongxiao Yang, Jinxin Guo, Xiufang Liu, Xueying Zhang and Yanzhao Yang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 23) pp:NaN6948-6948
Publication Date(Web):2013/04/04
DOI:10.1039/C3TA10487G
In this paper, a simple one-step hydrothermal method has been developed to prepare three-dimensional CeO2 microflower structures via a cerium oxalate precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM) and thermal gravimetric (TG) analysis were utilized to characterize the products. Herein, unlike the conventional calcination of a cerium oxalate precursor, oxalic acid acted not only as a precipitator but also as a modifier of morphology with a defined amount of C2O42−, while hydrogen peroxide (H2O2) was introduced as an oxidant to make the full conversion from Ce2(C2O4)3·10H2O to CeO2 in the hydrothermal process with the preserved flowerlike morphology. The as-obtained CeO2 microflowers displayed a high surface area of 147.6 m2 g−1 and narrow pore size of 3.759 nm by N2 adsorption and desorption measurement, and the H2-TPR test showed its better reduction behavior. Furthermore, CeO2 microflowers with hierarchical structures presented a higher catalytic activity for CO oxidation.
Co-reporter:Wei Liu, Wenzhi Wang, Ke Tang, Jinxin Guo, Yuqing Ren, Shuping Wang, Lijun Feng and Yanzhao Yang
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 7) pp:NaN2434-2434
Publication Date(Web):2015/11/19
DOI:10.1039/C5CY01241D
In this paper, a series of well-dispersed nickel–ceria catalysts with high surface area were successfully fabricated using a simple solvothermal approach and characterized by XRD, TEM, EDS, N2-sorption, Raman and TPR techniques. The results show that the amount of nickel species can have an impact on the morphology of the nickel–ceria catalysts, i.e. the hollow structure, particle size and porous structures. The prepared nickel–ceria samples (with the atomic ratio Ni:Ce (At% (Ni/Ce)) at approximately 6.58%) exhibit high catalytic performance in carbon monoxide (CO) oxidation with 100% conversion at 200 °C. The XRD, Raman, XPS and H2-TPR data confirm that the nickel species are the main promoting factor in the catalysis, including the doped nickel species, highly dispersed free NiO and the interfacial Ni–[O]–Ce structures. Further, the as-prepared nickel–ceria catalysts show high stability in the catalysis.
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 11) pp:
Publication Date(Web):
DOI:10.1039/C4AY00594E
The hypochromic effect of bromocresol green (BCG) resulted from long-chained imidazolium ionic liquids was investigated. The hypochromic effect may be caused by the formation of the neutral complex [Cnmim]2+[BCG]2−via electrostatic interaction and hydrophobic interaction. Based on the spectral characteristics, a new method for determination of long-chained imidazolium ionic liquids is developed. The proposed method can be performed using a UV-vis spectrophotometer, at the optimum λmin. Beer's law is obeyed in the concentration range of 0.004–0.04 mmol L−1 for [C14mim]Br and [C16mim]Cl, and the detection limits are 0.0011 and 0.00095 mmol L−1 for [C14mim]Br and [C16mim]Cl, respectively. Meanwhile, precision, accuracy and tolerance are also very good. The method is fast, economical and does not require organic solvents; it can be applied for determination of long-chained imidazolium ionic liquids.
![5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid,7-[[(2Z)-2-(2-furanyl)-2-(methoxyimino)acetyl]amino]-3-(hydroxymethyl)-8-oxo-,(6R,7R)-](http://img.cochemist.com/ccimg/56300/56271-94-4.png)
![5-Thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylicacid,7-[[(2Z)-2-(2-furanyl)-2-(methoxyimino)acetyl]amino]-3-(hydroxymethyl)-8-oxo-,(6R,7R)-](http://img.cochemist.com/ccimg/56300/56271-94-4_b.png)
