Co-reporter:Bo Li, Zhujun Xiao, Jiantao Zai, Ming Chen, Honghui Wang, Xuejiao Liu, Guan Li, Xuefeng Qian
Materials Today Energy 2017 Volume 5(Volume 5) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.mtener.2017.07.006
•Exterior carbon-coated porous Si/C microparticles were rational designed and prepared.•Reduced surface area with low content of carbon (5.8 wt %) and unfilled interior pores.•The initial Coulombic efficiency of the as-prepared Si/C microparticles reached to 87.5%.Cycling stability of Si anode materials has been significantly improved, but there was rare progress on its initial Coulombic efficiency, which is an essential factor for the overall capacity and energy density of full batteries. The challenge is to fabricate porous Si/C materials with small surface area by depositing carbon as less as possible and maintaining the interior porous structure of Si to achieve high initial Coulombic efficiency and good cycling stability at the same time. Herein, porous Si microparticles with pore size of ∼2.8 nm were successfully prepared. The surface area could be significantly reduced from 235.6 m2 g−1 to 32.4 m2 g−1 by coating carbon as low as 5.8 wt % because the narrow external openings of pores on Si microparticle were easily closed to leave the interior pores unfilled. As a result, the initial Coulombic efficiency of the as-prepared Si/C microparticles reached to 87.5% with a high reversible capability of 2242 mAh g−1 at 0.4 A g−1 after 100 cycles and long-term cycling stability (886 mAh g−1 at 2 A g−1 after 500 cycles).Download high-res image (251KB)Download full-size image
Co-reporter:Bo Li;Zhujun Xiao;Ming Chen;Ziyue Huang;Xiaoyong Tie;Jiantao Zai
Journal of Materials Chemistry A 2017 vol. 5(Issue 46) pp:24502-24507
Publication Date(Web):2017/11/28
DOI:10.1039/C7TA07088H
Inspired by nature, both high-performance Si/C and activated carbon (AC) energy storage materials with a hierarchically biomimetic structure can be prepared from rice husks (RHs), and further serve as promising anode and cathode materials for hybrid lithium-ion capacitors (LICs), respectively. Benefitting from the high capacity and good rate and cycling performances of the Si/C anode material and RH-derived AC (RAC) cathode material, the designed Si/C||RAC LICs give a high energy density of 227 W h kg−1 at a power density of 1146 W kg−1, and ∼181 W h kg−1 can still be retained even at an ultra-high power density of ∼32 595 W kg−1. Furthermore, the RH-derived LICs also show a long-term cycling stability (16 000 cycles at ∼16 800 W kg−1).
Co-reporter:Yuanyuan Liu;Jiantao Zai;Xiaomin Li;Zi-feng Ma
Dalton Transactions 2017 vol. 46(Issue 4) pp:1260-1265
Publication Date(Web):2017/01/24
DOI:10.1039/C6DT04467K
Transition metal sulfides with high specific capacity have received increasing research interest in lithium storage. However, the low reversibility of metal sulfides usually leads to the oxidation of Li2S into polysulfides. The dissolution of polysulfides will suppress the regeneration of sulfides due to the loss of Li2S, which usually leads to poor cycling stability of sulfides. Herein, Al2O3 coated Ni3S4 nanoparticles (Ni3S4@Al2O3) have been rationally designed and fabricated via a one-pot hydrothermal process. The regeneration of nickel sulfides, which is the key to cycling stability of sulfides, can be promoted by the localized conversion from metal to metal sulfides because the Al2O3 layer can prevent the diffusion and dissolution of polysulfides. The conversion of Al2O3 to ion-conductive AlF3 can enhance the quick charge transfer process of the lithium ion insertion/extraction reaction. Furthermore, the Al2O3/AlF3 layer can also prevent the growth and aggregation of Ni3S4 nanoparticles to retain the structure of the electrodes during the cycling process. The as-prepared Ni3S4@Al2O3 exhibits a high reversible capacity of 651 mA h g−1 at 500 mA g−1 even after 400 cycles. This method can also be extended to other metal sulfides for improving electrochemical performances.
Co-reporter:Minmin Zhang;Jiantao Zai;Jie Liu;Ming Chen;Zeren Wang;Guan Li;Liwu Qian;Xibin Yu
Dalton Transactions 2017 vol. 46(Issue 29) pp:9511-9516
Publication Date(Web):2017/07/25
DOI:10.1039/C7DT01511A
Transition metal sulfides are a kind of potential candidates for efficient and stable CE materials in DSSCs due to their good electrocatalytic ability and stability towards I3− reduction. However, the low conductivity of sulfides is harmful for the electron collection and transfer process, and the absorption/desorption and diffusion process of I−/I3− should be optimized to achieve high electrocatalytic activity over Pt. Herein, a hierarchical CoFeS2/reduced graphene oxide (CoFeS2/rGO) composite was rationally designed and prepared via the in situ conversion of CoFe layer double hydroxide anchored on rGO. Due to the synergistic effects of Co and Fe, unique 3D hierarchical structures formed by nanosheets, and the conductivity of rGO, the CoFeS2/rGO CEs exhibited good electrocatalytic activity and stability towards the reduction of I3− to I−, and the DSSCs could also achieve a high efficiency of 8.82%, higher than those of the devices based on Pt (8.40%) and pure CoFeS2 (8.30%) CEs. Moreover, the devices also showed the characteristics of fast activity onset, good stability, and high multiple start/stop capability. The results indicated that the developed CoFeS2/rGO composite could be a promising alternative for Pt in DSSCs.
Co-reporter:Yinglin Xiao;Jiantao Zai;Bingbing Tian
Nano-Micro Letters 2017 Volume 9( Issue 3) pp:
Publication Date(Web):2017 July
DOI:10.1007/s40820-017-0127-7
A NiFe2O4/expanded graphite (NiFe2O4/EG) nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-ion battery. The obtained nanocomposite exhibited a good cycle performance, with a capacity of 601 mAh g−1 at a current of 1 A g−1 after 800 cycles. This good performance may be attributed to the enhanced electrical conductivity and layered structure of the EG. Its high mechanical strength could postpone the disintegration of the nanocomposite structure, efficiently accommodate volume changes in the NiFe2O4-based anodes, and alleviate aggregation of NiFe2O4 nanoparticles.
Co-reporter:Jiantao Zai;Yuanyuan Liu;Xiaomin Li;Zi-feng Ma;Rongrong Qi
Nano-Micro Letters 2017 Volume 9( Issue 2) pp:
Publication Date(Web):2017 April
DOI:10.1007/s40820-016-0121-5
Three-dimensional (3D) flower-like Co–Al layered double hydroxide (Co–Al-LDH) architectures composed of atomically thin nanosheets were successfully synthesized via a hydrothermal method in a mixed solvent of water and butyl alcohol. Owing to the unique hierarchical structure and modification by butyl alcohol, the electrochemical stability and the charge/mass transport of the Co–Al-LDHs was improved. When used in supercapacitors, the obtained Co–Al-LDHs deliver a high specific capacitance of 838 F g−1 at a current density of 1 A g−1 and excellent rate performance (753 F g−1 at 30 A g−1 and 677 F g−1 at 100 A g−1), as well as excellent cycling stability with 95% retention of the initial capacitance even after 20,000 cycles at a current density of 5 A g−1. This work provides a promising alternative strategy to enhance the electrochemical properties of supercapacitors.
Co-reporter:Shoushuang Huang, Jiantao Zai, Dui Ma, Zhangjun Hu, Qingquan He, Minghong Wu, Dayong Chen, Zhiwen Chen, Xuefeng Qian
Electrochimica Acta 2017 Volume 241(Volume 241) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.electacta.2017.04.116
•1D Ni3S4-PtCo heteronanorods are synthesized by a facile method.•The formed M-S heterojunctions enhance the catalytic activity of I3−.•The DSSCs with Ni3S4-PtCo HNRs yield a high PCE of 8.66%.•The hybrid CEs significantly reduce the cost.Metal-semiconductor based Mott-Schottky (M-S) heterojunctions combining two or more functionalities in one unit can effectively improve their catalytic activity and durability due to the electronic coupling effects between distinct components. Although tremendous progress has been made in structure fabrication, controllable synthesis of one-dimensional (1D) M-S heterojunction and its application as electrocatalysts is still lacking. Herein, uniform and well-defined 1D Ni3S4-PtCo heteronanorods are synthesized via a facile solution method and employed as counter electrode (CE) catalyst in the dye-sensitized solar cells (DSSCs). By exploiting the benefits of both structural and compositional characteristics, namely, the direct electrical pathways of 1D nanostructure, optimized work function of metal alloy as well as the synergistic effect between Ni3S4 and PtCo, the as-designed Ni3S4-PtCo heteronanorods exhibit excellent catalytic activity and stability toward the reduction of triiodide in DSSCs. A DSSC with Ni3S4-PtCo achieves a high power conversion efficiency of 8.66% under AM1.5G illumination (100 mW cm−2), higher than that of pristine Pt-based device (8.12%). Moreover, the fast activity onset and relatively long stability further demonstrate that the Ni3S4-PtCo heteronanorod is a promising alternative to Pt in DSSCs. Considering the diversity of structures and components in heterostructures, the strategy presented here can be extended for synthesizing other well-defined 1D M-S heterojunctions, which may be used in the fields of catalysis, energy conversion and storage.Download high-res image (187KB)Download full-size image
Co-reporter:Yinglin Xiao, Jiantao Zai, Xuefeng Qian
Journal of Alloys and Compounds 2017 Volume 716(Volume 716) pp:
Publication Date(Web):5 September 2017
DOI:10.1016/j.jallcom.2017.04.259
•Multiporous NiMnO3 micro-nano structure spheres are been synthesized.•Its composites with graphene show excellent electrochemical performances.•The multiporous micro-nano structure spheres can alleviate the side reaction of electrolyte.Transition metal oxide nanomaterials have been applied in developing high capacity lithium ion batteries. However, transition metal oxide nanomaterials have some major issues to be addressed, including nanomaterials aggregation, severe side reactions and low conductivity. Herein, multiporous NiMnO3 micro-nano structure spheres are been synthesized, and their composites with graphene sheets (GNSs) have been prepared. The obtained multiporous NiMnO3 micro-nano structure graphene composites show excellent electrochemical performances with a high reversible capacity of 582 mA h g−1 at a current of 1 A g−1 after 150 cycles and 914 mA h g−1 at a current of 0.1 A g−1 after 50 cycles without obvious side reaction. The result shows the multiporous NiMnO3-GNSs micro-nano structure spheres can alleviate the side reaction of electrolyte.Transition metal oxide nanomaterials have been applied in developing high capacity lithium ion batteries. However, transition metal oxide nanomaterials have some major issues to be addressed, including nanomaterials aggregation, severe side reactions and low conductivity. Herein, multiporous NiMnO3 micro-nano structure spheres are been synthesized, and their composites with graphene sheets (GNSs) have been prepared. The obtained multiporous NiMnO3 micro-nano structure graphene composites show excellent electrochemical performances with a high reversible capacity of 582 mA h g−1 at a current of 1 A g−1 after 150 cycles and 914 mA h g−1 at a current of 0.1 A g−1 after 50 cycles without the increased capacities caused by the side reaction are been detected. The result shows the multiporous NiMnO3-GNSs micro-nano structure spheres can alleviate the side reaction of electrolyte.Download high-res image (224KB)Download full-size image
Co-reporter:Min Wang, Jiantao Zai, Bo Li, Yan Wang, Shoushuang Huang, Qingquan He and Xuefeng Qian
Journal of Materials Chemistry A 2016 vol. 4(Issue 13) pp:4790-4796
Publication Date(Web):01 Mar 2016
DOI:10.1039/C6TA00184J
Hierarchical Cu2−XSe nanotubes, constructed by nanosheets with a thickness of two unit cells (1.2 nm), have been fabricated with Cu(OH)2 nanorod arrays as self-sacrificial templates at room temperature, with a high surface area of 72.3 m2 g−1. The unique structure of the Cu2−XSe nanotubes leads to high electrocatalytic activity towards the reduction of polysulfides, given their enlarged active surface area, rapid transportation of electrons and mass. As a result, quantum dot-sensitized solar cells (QDSSCs) with the obtained Cu2−XSe nanotubes as the counter electrode material exhibit long-term stability and a high power conversion efficiency of 5.14% (1 sun irradiation simulation), better than those of the commonly-used Cu2S/brass (3.38%) and reference Pt (1.78%) electrodes.
Co-reporter:Xiaomin Li, Jiantao Zai, Yuanyuan Liu, Xiaobo He, Shijie Xiang, Zifeng Ma, Xuefeng Qian
Journal of Power Sources 2016 Volume 325() pp:675-681
Publication Date(Web):1 September 2016
DOI:10.1016/j.jpowsour.2016.06.090
•3D microspheres are built by atomically thin NiFe layered double hydroxides (LDHs).•Citrate and butanol paly key actions on the formation of atomically thin 3D LDHs.•The atomically thin 3D LDHs exhibit excellent activity and stability in the OER.•A high specific capacitance about 1061 F g−1 at 1 A g−1 of NiFe-LDHs is obtained.LDHs in atomic thickness (mono-/bi-layers) usually exhibit novel physicochemical properties, especially in surface-dependent energy storage and catalysis areas. However, the thickness of the commonly reported 2D LDHs is in nanoscale and the bottom-up synthesis of atomically thin LDHs is rarely reported. Herein, high-quality atomically thin layered NiFe-LDHs assembled 3D microspheres were synthesized via a rational designed reaction system, where the formation of atomically thin building blocks was controlled by the synergetic effects of released carbonate anions and butanol. Furthermore, the complexant and solvents played important effects on the process of coprecipitation and the assembling of LDHs. Due to the nature of atomically thin LDHs nanosheets and unique 3D hierarchical structures, the obtained microspheres exhibited excellent electrocatalytic oxygen evolution reaction (OER) activity in alkaline medium with an onset overpotential (0.435 V, which is lower than that of common LDHs) and good durability. The as-prepared 3D NiFe-LDHs microspheres were also firstly used as supercapacitor materials and displayed a high specific capacitance of 1061 F g−1 at the current density of 1 A g−1.
Co-reporter:Bo Li;Xiaomin Li;Jiantao Zai
Nano-Micro Letters 2016 Volume 8( Issue 2) pp:174-181
Publication Date(Web):2016 April
DOI:10.1007/s40820-015-0075-z
Porous Zn–Sn–O nanocubes with a uniform size were synthesized through a facile aqueous solution route combined with subsequent thermal treatment. The chemical composition, morphology, and microstructure of Zn–Sn–O nanocubes, which have significant effects on the lithium storage performances, were easily tuned by adjusting the calcination temperature in preparation processes of ZnSn(OH)6 solid nanocubes. Further studies revealed that porous Zn–Sn–O nanocubes prepared at 600 °C exhibited a good rate capability and a high reversible capacity of 700 mAh g−1 at a current density of 200 mA g−1 after 50 cycles, which may be a great potential as anode materials in Lithium-ion batteries.
Co-reporter:Shoushuang Huang, Qingquan He, Jiantao Zai, Min Wang, Xiaomin Li, Bo Li and Xuefeng Qian
Chemical Communications 2015 vol. 51(Issue 43) pp:8950-8953
Publication Date(Web):21 Apr 2015
DOI:10.1039/C5CC02584B
Metastable wurtzstannite Cu2ZnGeS4 (CZGS) nanocrystals were synthesized via a hot-injection method and then used as matrixes to fabricate PtCo–CZGS heterostructured nano-particles. The formed Mott–Schottky heterojunctions in the hybrid nanocrystals promote the transfer of electrons from semiconducting CZGS to metallic PtCo, which accelerates the reduction of I3− to I− in dye-sensitized solar cells.
Co-reporter:Nirmal Adhikari, Ashish Dubey, Devendra Khatiwada, Abu Farzan Mitul, Qi Wang, Swaminathan Venkatesan, Anastasiia Iefanova, Jiantao Zai, Xuefeng Qian, Mukesh Kumar, and Qiquan Qiao
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 48) pp:26445
Publication Date(Web):November 18, 2015
DOI:10.1021/acsami.5b09797
We report effects of an interface between TiO2–perovskite and grain–grain boundaries of perovskite films prepared by single step and sequential deposited technique using different annealing times at optimum temperature. Nanoscale kelvin probe force microscopy (KPFM) measurement shows that charge transport in a perovskite solar cell critically depends upon the annealing conditions. The KPFM results of single step and sequential deposited films show that the increase in potential barrier suppresses the back-recombination between electrons in TiO2 and holes in perovskite. Spatial mapping of the surface potential within perovskite film exhibits higher positive potential at grain boundaries compared to the surface of the grains. The average grain boundary potential of 300–400 mV is obtained upon annealing for sequentially deposited films. X-ray diffraction (XRD) spectra indicate the formation of a PbI2 phase upon annealing which suppresses the recombination. Transient analysis exhibits that the optimum device has higher carrier lifetime and short carrier transport time among all devices. An optimum grain boundary potential and proper band alignment between the TiO2 electron transport layer (ETL) and the perovskite absorber layer help to increase the overall device performance.Keywords: back recombination; charge transport; interface engineering; Kelvin probe force microscopy; perovskite film
Co-reporter:Min Wang, Wenlong Chen, Jiantao Zai, Shoushuang Huang, Qingquan He, Wei Zhang, Qiquan Qiao, Xuefeng Qian
Journal of Power Sources 2015 Volume 299() pp:212-220
Publication Date(Web):20 December 2015
DOI:10.1016/j.jpowsour.2015.09.008
•Hierarchical Cu7S4 nanotubes (Cu7S4-HNT) have been synthesized at room temperature.•Cu7S4-HNT combine the advantages of nanotube and hierarchical structure.•The Cu7S4-HNT CE is stable in electrolyte even after 1000 CV cycles.•The high stable CEs possess a high power conversion efficiency of 4.53%.•The abundant active sites and fast mass/electron transfer lead to good properties.As a kind of promising generation solar cells, the catalytic properties of counter electrodes (CEs) play a key factor on the performance of QDSSCs (quantum dot-sensitized solar cells) at present. Here, hierarchical Cu7S4 nanotubes (Cu7S4-HNT) assembled by hexagonal nanoplates have been prepared by an in-situ growth route and etching process at room temperature. The formation mechanism of the unique morphology is also proposed. Because of the rapid diffusion of electrons and electrolyte, abundant catalytic sites and high stability, the as-prepared Cu7S4-HNT combined the characteristics of nanotube and hierarchical structure can improve the catalytic performance of CEs. QDSSCs based on the Cu7S4-HNT CEs possess a high power conversion efficiency of 4.53%, superior to those with the commonly used Cu2S/brass (3.3%) or the referenced Pt (1.79%) CEs. What's more, the Cu7S4-HNT CE still shows excellent stability in electrolyte after 1000 CV cycles.
Co-reporter:Na Liang, Wenlong Chen, Fang Dai, Xiangyang Wu, Wei Zhang, Zhi Li, Jingmei Shen, Shoushuang Huang, Qingquan He, Jiantao Zai, Nenghu Fang and Xuefeng Qian
CrystEngComm 2015 vol. 17(Issue 9) pp:1902-1905
Publication Date(Web):03 Feb 2015
DOI:10.1039/C4CE02405B
Homogenously hexagonal prismatic AgBiS2 nanocrystals with sizes of about 7.6 nm have been synthesized by the selective absorption of oleylamine and anisotropic growth in a mixed solvent system. Quantum dot-sensitized solar cells with the as-prepared AgBiS2 nanocrystals as counterelectrode materials showed a conversion efficiency of 2.09% compared with that of Pt (1.73%).
Co-reporter:Jiantao Zai and Xuefeng Qian
RSC Advances 2015 vol. 5(Issue 12) pp:8814-8834
Publication Date(Web):16 Dec 2014
DOI:10.1039/C4RA11903G
Because of the huge energy and environmental problems caused by the use of fossil fuels, R&D on innovative energy storage systems has never become so important as today. Although there are still some safety, energy, power and cost issues because of which electric vehicles are becoming more and more common in our daily life, such as E-bikes or E-cars. This paper provides an overview of the recent progress on three dimensional (3D) metal oxides–graphene (MOs–G) composites as advanced electrode materials in lithium ion batteries (LIBs). Beginning with a brief description of the importance and preparation methods of 3D MOs–G composites, the effects of the morphology and size of metal oxides (MOs) or graphene on composites for LIBs are then systematically reviewed and discussed. Additionally, important effects of composition and interactions between metal oxides and graphene are also pointed out. Finally, the future challenges of MOs–G composites for lithium ion batteries are discussed.
Co-reporter:Miao Xu;Tiannan Ye;Dr. Fang Dai;Jindi Yang;Dr. Jingmei Shen;Qingquan He;Wenlong Chen;Na Liang;Dr. Jiantao Zai; Xuefeng Qian
ChemSusChem 2015 Volume 8( Issue 7) pp:1218-1225
Publication Date(Web):
DOI:10.1002/cssc.201403334
Abstract
In most of the reported n–n heterojunction photocatalysts, both the conduction and valence bands of one semiconductor are more negative than those of the other semiconductor. In this work, we designed and synthesized a novel n–n heterojunction photocatalyst, namely CdS-ZnWO4 heterojunctions, in which ZnWO4 has more negative conduction band and more positive valence band than those of CdS. The hydrogen evolution rate of CdS-30 mol %-ZnWO4 reaches 31.46 mmol h−1 g−1 under visible light, which is approximately 8 and 755 times higher than that of pure CdS and ZnWO4 under similar conditions, respectively. The location of the surface active sites is researched and a plausible mechanism of performance enhancement by the tuning of the structure is proposed based on the photoelectrochemical characterization. The results illustrate that this kind of nonconventional n–n heterojunctions is also suitable and highly efficient for solar hydrogen evolution.
Co-reporter:Qingquan He;Shoushuang Huang;Dr. Jiantao Zai;Nianqi Tang;Bo Li; Qiquan Qiao; Xuefeng Qian
Chemistry - A European Journal 2015 Volume 21( Issue 43) pp:15153-15157
Publication Date(Web):
DOI:10.1002/chem.201502337
Abstract
It is generally believed that silver or silver-based compounds are not suitable counter electrode (CE) materials for dye-sensitized solar cells (DSSCs) due to the corrosion of the I−/I3− redox couple in electrolytes. However, Ag2S has potential applications in DSSCs for catalyzing I3− reduction reactions because of its high carrier concentration and tiny solubility product constant. In the present work, CE manufactured from Ag2S nanocrystals ink exhibited efficient electrocatalytic activity in the reduction of I3− to I− in DSSCs. The DSSC consisting of Ag2S CE displayed a higher power conversion efficiency of 8.40 % than that of Pt CE (8.11 %). Moreover, the devices also showed the characteristics of fast activity onset, high multiple start/stop capability and good irradiated stability. The simple composition, easy preparation, stable chemical property, and good catalytic performance make the developed Ag2S CE as a promising alternative to Pt CE in DSSCs.
Co-reporter:Qingquan He;Shoushuang Huang; Cheng Wang; Qiquan Qiao;Na Liang;Miao Xu;Wenlong Chen;Dr. Jiantao Zai; Xuefeng Qian
ChemSusChem 2015 Volume 8( Issue 5) pp:817-820
Publication Date(Web):
DOI:10.1002/cssc.201403343
Abstract
Well-defined uniform pyramidal Ag–Ag8SnS6 heterodimers are prepared via a one-pot method. A plausible formation mechanism for the unique structures based on a seed-growth process and an etching effect due to oleylamine is proposed. The formed metal–semiconductor Mott–Schottky heterojunction promotes electron transfer from semiconducting Ag8SnS6 to metallic Ag, which catalyzes the reduction of I3− to I−. When used as counter electrode in dye-sensitized solar cells, the heterodimers show comparable performance to platinum.
Co-reporter:Shoushuang Huang;Qingquan He;Wenlong Chen; Qiquan Qiao;Dr. Jiantao Zai; Xuefeng Qian
Chemistry - A European Journal 2015 Volume 21( Issue 10) pp:4085-4091
Publication Date(Web):
DOI:10.1002/chem.201406124
Abstract
Two-dimensional (2D) semiconducting nanosheets have emerged as an important field of materials, owing to their unique properties and potential applications in areas ranging from electronics to catalysis. However, the controlled synthesis of ultrathin 2D nanosheets remains a great challenge, due to the lack of an intrinsic driving force for anisotropic growth. High-quality ultrathin 2D FeSe2 nanosheets with average thickness below 7 nm have been synthesized on large scale by a facile solution method, and a formation mechanism has been proposed. Due to their favorable structural features, the as-synthesized ultrathin FeSe2 nanosheets exhibit excellent electrocatalytic activity for the reduction of triiodide to iodide and low charge-transfer resistance at the electrolyte–electrode interface in dye-sensitized solar cells (DSSCs). The DSSCs with FeSe2 nanosheets as counter electrode material achieve a high power conversion efficiency of 7.53 % under a simulated solar illumination of 100 mW cm−2 (AM 1.5), which is comparable with that of Pt-based devices (7.47 %).
Co-reporter:Alex Aboagye, Hytham Elbohy, Ajit D. Kelkar, Qiquan Qiao, Jiantao Zai, Xuefeng Qian, Lifeng Zhang
Nano Energy 2015 Volume 11() pp:550-556
Publication Date(Web):January 2015
DOI:10.1016/j.nanoen.2014.10.033
•Carbon nanofibers with controllable surface-attached Pt nanoparticles (ECNFs-PtNPs) were prepared by electrospinning followed by carbonization and subsequent Pt nanoparticle growth through redox reaction.•The hierarchical ECNFs-PtNPs were employed as cost-effective counter electrode in dye-sensitized solar cells (DSCs).•The effects of size, morphology, and loading of Pt nanoparticles on performance of DSCs were investigated.•DSCs with ECNFs-PtNPs counter electrode demonstrated excellent solar power conversion efficiency which is equivalent or even higher than that of conventional DSCs made with Pt counter electrode.Dye-sensitized solar cells (DSCs) have attracted incredible attention in recent years as relatively inexpensive alternative to silicon solar cells. Conventionally, a transparent fluoride-doped tin oxide (FTO) conductive glass with a thin layer coating of platinum (Pt) is used as counter electrode in DSCs. The widespread use of Pt as counter electrode in DSCs is due to its catalytic capability for I3- reduction in electrolyte. However, Pt is costly and can be affected by the corrosive nature of I-/I3- redox couple, which makes it a less desirable candidate for use in industrial scale manufacturing. In this study, carbon nanofibers with surface-attached Pt nanoparticles were prepared by stabilization and carbonization of electrospun polyacrylonitrile (PAN) nanofibers and subsequent controllable Pt nanoparticle growth on the obtained carbon nanofiber surface through redox reaction. The hierarchical carbon nanofibers with surface-attached Pt nanoparticles (ECNFs-PtNPs) were then employed as cost-effective counter electrode in DSCs. The effects of size, morphology, and loading of Pt nanoparticles on performance of DSCs were investigated. Compared to conventional counter electrode, the counter electrode that was made of ECNFs-PtNPs exhibited larger open circuit voltage (Voc). The DSCs that were made with ECNFs-PtNPs counter electrode demonstrated excellent solar energy conversion efficiencies in the range of 7% to 8%.
Co-reporter:Shoushuang Huang, Qingquan He, Wenlong Chen, Jiantao Zai, Qiquan Qiao, Xuefeng Qian
Nano Energy 2015 Volume 15() pp:205-215
Publication Date(Web):July 2015
DOI:10.1016/j.nanoen.2015.04.027
•3D FeSe2 microspheres were controlled synthesized by selective adsorption of alkythiols though hot-injection method.•3D FeSe2 microspheres constructed by ultrathin 2D nanosheets can provide abundant active sites and facilitate the diffusion of electrolyte, exhibiting comparable catalytic activity to Pt.•The FeSe2 NSs CE exhibited better stable capability than Pt toward iodine-based electrolyte.Mastery over the structures at nano/microscale can effectively tailor the catalytic activity and durability of materials. Herein, three dimension (3D) hierarchical iron diselenide (FeSe2) microspheres have been successfully synthesized via a hot-injection method. The morphologies of building blocks and final products can be simply controlled by the amount and/or the type of alkythiols, from irregular micro/nanoparticles to uniform 3D hierarchical microspheres made of ultrathin nanosheets or rhombus-like nanorods. A formation mechanism has been understood based on the inherent crystal structure of FeSe2 and the selective adsorption of alkythiols. The as-obtained FeSe2 samples were employed as counter electrode (CE) materials in dye-sensitized solar cells (DSSCs). Electrochemical characterizations indicated that the 3D hierarchical FeSe2 microspheres composed of ultrathin nanosheets (FeSe2 NSs) exhibited low charge transfer resistance at the electrolyte–electrode interface, high electrocatalytic activity and fast reaction kinetics for the I−/I3− redox reaction. A DSSC with FeSe2 NSs CE achieved a high power conversion efficiency of 8.39% under a simulated solar illumination of 100 mW cm−2 (AM 1.5), comparable to that of Pt based devices (8.20%). Moreover, the fast activity onset and relatively long stability demonstrated that the FeSe2 NSs is a promising alternative to Pt in DSSC.
Co-reporter:Na Liang, Jiantao Zai, Miao Xu, Qi Zhu, Xiao Wei and Xuefeng Qian
Journal of Materials Chemistry A 2014 vol. 2(Issue 12) pp:4208-4216
Publication Date(Web):20 Dec 2013
DOI:10.1039/C3TA13931J
Novel Bi2S3/Bi2O2CO3 heterojunction photocatalysts were prepared by a simple chemical reaction from commercial Bi2O2CO3. The photocatalytic activities of Bi2S3/Bi2O2CO3 were evaluated by degrading Rhodamine B (RhB) under visible light and sunlight irradiation. Further investigation revealed that the content of loading bismuth sulfide (Bi2S3) had important effects on the photocatalytic activity of the Bi2S3/Bi2O2CO3 heterojunctions, and the 5 mol% Bi2S3/Bi2O2CO3 heterojunction photocatalyst exhibited the best photocatalytic activity (30 min under visible light, λ > 400 nm). The high photocatalytic activity could be attributed to its good visible light absorption, facilitated charge separation of photogenerated electron–hole pairs and efficient charge transfer path in the partly exposed core in the heterojunctions. These benefits are derived from the unique band gap structure of the Bi2S3/Bi2O2CO3 n–n-type heterojunctions and special morphology with the partly exposed core, which was confirmed by photoluminescent spectra, surface photovoltage spectra and photoelectrochemical characterizations.
Co-reporter:Na Liang, Min Wang, Lun Jin, Shoushuang Huang, Wenlong Chen, Miao Xu, Qingquan He, Jiantao Zai, Nenghu Fang, and Xuefeng Qian
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 14) pp:11698
Publication Date(Web):June 24, 2014
DOI:10.1021/am502481z
Ag2O/Bi2O2CO3 p-n heterojunctions are prepared with commercial Bi2O2CO3 as precursor via a simple photosynthesis process. The obtained Ag2O/Bi2O2CO3 p-n heterojunctions show higher photocatalytic activity than that of pure n-Bi2O2CO3, and the obtained Ag2O/Bi2O2CO3 (AB-4) heterojunction exhibits the best photocatalytic activity under visible light (λ > 400 nm), with which Rhodamine B, methyl blue and methyl orange can be completely degraded within 12 min. Photoluminescent spectra and photoelectrochemical measurement further indicate that the Ag2O/Bi2O2CO3 p-n heterojunctions greatly enhance the charge generation and suppress the charge recombination of photogenerated electron–hole pairs, which would be beneficial to improve their photocatalytic activity.Keywords: Ag2O; Ag2O/Bi2O2CO3; Bi2O2CO3; p-n heterojunctions; photocatalytic activity; visible light
Co-reporter:Bo Li, Jiantao Zai, Yinglin Xiao, Qianyan Han and Xuefeng Qian
CrystEngComm 2014 vol. 16(Issue 16) pp:3318-3322
Publication Date(Web):03 Feb 2014
DOI:10.1039/C3CE42659A
Biomorphic SnO2/C composites were synthesized by a facile biotemplating method using natural cotton as the structure template and the bio-carbon source. The content of carbon in the composites could be easily adjusted by varying the sintering temperature. Electrochemical tests demonstrated that the content of carbon in the obtained composites had great effects on their electrochemical performances, such that the biomorphic SnO2/C composites prepared at 300 °C exhibited a reversible capacity of 530 mAh g−1 after 100 cycles at a current density of 100 mA g−1. The results suggest that the obtained biomorphic SnO2/C composites prepared by the facile approach may be used as anode materials in practical lithium-ion batteries.
Co-reporter:Na Liang, Qingquan He, Shoushuang Huang, Min Wang, Wenlong Chen, Miao Xu, Yanping Yuan, Jiantao Zai, Nenghu Fang and Xuefeng Qian
CrystEngComm 2014 vol. 16(Issue 43) pp:10123-10130
Publication Date(Web):22 Aug 2014
DOI:10.1039/C4CE01239A
AgInxGa1−xS2 (x = 0, 0.3, 0.5, 0.7 and 1) solid solutions with a size of 25–100 nm have been synthesized in a mixed solvent system via a solvothermal process. The crystal structure of the solid solutions gradually transforms from tetragonal to orthorhombic, along with the chemical composition (x value changes from 0 to 1), and the band gap of the solid solutions can be tuned from 2.37 eV to 1.62 eV. Further studies revealed that the obtained AgInxGa1−xS2 solid solutions show improved photocatalytic activities under visible light irradiation compared with AgGaS2 and AgInS2, and the AgIn0.3Ga0.7S2 solid solution exhibits the best photocatalytic performance for its optimized band gap and energy structure.
Co-reporter:Miao Xu;Min Wang;Tiannan Ye;Na Liang;Lun Jin;Dr. Jiantao Zai; Xuefeng Qian
Chemistry - A European Journal 2014 Volume 20( Issue 42) pp:13576-13582
Publication Date(Web):
DOI:10.1002/chem.201403683
Abstract
Hydrogen produced from water under solar energy is an ideal clean energy source, and the efficiency of hydrogen production usually depends on the catalytic systems based on new compounds and/or a unique nanostructure. Herein, well-defined cube-in-cube hollow Cu9S5 nanostructures have been successfully prepared with Cu2O nanocubes and CS2 as precursors, and single-shell hollow Cu9S5 nanocubes could be obtained by replacing CS2 with Na2S. The formation mechanism of cube-in-cube hollow nanostructures has been proposed based on the Kirkendell effect and an outward self-assembly process. Further studies revealed that the cube-in-cube hollow Cu9S5 nanostructures exhibited better photocatalytic activity toward solar H2 evolution and would be a promising photocatalyst in the solar hydrogen industry.
Co-reporter:Miao Xu;Min Wang;Tiannan Ye;Na Liang;Lun Jin;Dr. Jiantao Zai; Xuefeng Qian
Chemistry - A European Journal 2014 Volume 20( Issue 42) pp:
Publication Date(Web):
DOI:10.1002/chem.201490174
Co-reporter:Miao Xu;Min Wang;Tiannan Ye;Na Liang;Lun Jin;Dr. Jiantao Zai; Xuefeng Qian
Chemistry - A European Journal 2014 Volume 20( Issue 42) pp:
Publication Date(Web):
DOI:10.1002/chem.201405003
Abstract
Invited for the cover of this issue is the group of Xuefeng Qian at Shanghai Jiao Tong University. The image depicts hydrogen being produced from water by solar energy. Read the full text of the article at 10.1002/chem.201403683.
Co-reporter:Amit Thapa;Jiantao Zai;Hytham Elbohy;Prashant Poudel;Nirmal Adhikari
Nano Research 2014 Volume 7( Issue 8) pp:1154-1163
Publication Date(Web):2014 August
DOI:10.1007/s12274-014-0478-z
Co-reporter:Yinglin Xiao, Jiantao Zai, Xiaomin Li, Yong Gong, Bo Li, Qianyan Han, Xuefeng Qian
Nano Energy 2014 Volume 6() pp:51-58
Publication Date(Web):May 2014
DOI:10.1016/j.nanoen.2014.03.006
•GNSs–PDA–NiFe2O4 synthesized by in-situ ultrasonic process shows 838 mAh g−1 at 1 A g−1 after 100 cycles.•The enhanced lithium storage performances can be attributed to the nature of PDA interlayers.•PDA interlayers can enhance the mechanical connections between GNSs/NiFe2O4 and build a conductive network.•Covalent nature of PDA can improve the wettability of composite in organic electrolyte and decrease charge transfer resistance.Polydopamine (PDA) functionalized graphene/NiFe2O4 (GNSs–PDA–NiFe2O4) nanocomposite has been successfully synthesized through an in-situ ultrasonic method. The obtained GNSs–PDA–NiFe2O4 nanocomposite shows a reversible capacity up to 947 mAh g−1 and much improved rate capability, e.g. delivering a capacity of 562 mAh g−1 at 5 A g−1, about 7 times higher than that of graphene/NiFe2O4 nanocomposite. The improvement in the rate capability of the obtained GNSs–PDA–NiFe2O4 nanocomposite can be attributed to the improved interactions between graphene and NiFe2O4 derived from PDA, and a high conductive network fabricated by PDA functionalized graphene, which can be supported by TEM images and EIS measurements. Further studies reveal the strong graphene–NiFe2O4 interactions are also beneficial for retaining the high conductive network after the charge–discharge processes, and further beneficial for its cyclic stability.
Co-reporter:Yinglin Xiao;Xiaomin Li;Jiantao Zai;Kaixue Wang;Yong Gong;Bo Li
Nano-Micro Letters 2014 Volume 6( Issue 4) pp:307-315
Publication Date(Web):2014 October
DOI:10.1007/s40820-014-0003-7
CoFe2O4-graphene nanosheets (CoFe2O4-GNSs) were synthesized through an ultrasonic method, and their electrochemical performances as Li-ion battery electrode were improved by annealing processes. The nanocomposites obtained at 350 °C maintained a high specific capacity of 1,257 mAh g−1 even after 200 cycles at 0.1 A g−1. Furthermore, the obtained materials also have better rate capability, and it can be maintained to 696, 495, 308, and 254 mAh g−1 at 1, 2, 5, and 10 A g−1, respectively. The enhancements realized in the reversible capacity and cyclic stability can be attributed to the good improvement in the electrical conductivity achieved by annealing at appropriate temperature, and the electrochemical nature of CoFe2O4 and GNSs during discharge–charge processes.
Co-reporter:Fukun Chen, Jiantao Zai, Miao Xu and Xuefeng Qian
Journal of Materials Chemistry A 2013 vol. 1(Issue 13) pp:4316-4323
Publication Date(Web):21 Jan 2013
DOI:10.1039/C3TA01491F
3D-hierarchical Cu3SnS4 flowerlike microspheres have been successfully synthesized through a solvothermal process. The reaction temperature and the dosage of the sulfur source play significant roles in the growth of Cu3SnS4 flowerlike microspheres. The formation process of the hierarchical microspheres is studied well and a possible mechanism is also proposed. UV-visible absorption spectra show that the as-synthesized Cu3SnS4 microspheres with a direct band gap of 1.38 eV have stronger absorption from the UV to near-IR region. Further studies reveal that the obtained Cu3SnS4 photocatalysts without any loadings exhibit good photocatalytic activity, and the rate of H2 evolution is determined to be 1.1 mmol h−1 g−1 under simulated solar irradiation.
Co-reporter:Jiantao Zai, Chao Yu, Liqi Tao, Miao Xu, Yinglin Xiao, Bo Li, Qianyan Han, Kaixue Wang and Xuefeng Qian
CrystEngComm 2013 vol. 15(Issue 34) pp:6663-6671
Publication Date(Web):19 Jun 2013
DOI:10.1039/C3CE40993G
Ni-doped NiO–reduced graphene oxide nanosheet (RGONS) nanocomposites as anode materials for Li ion batteries are synthesized through a solvothermal and calcination method. The obtained Ni-doped NiO–RGONS nanocomposites display an improved cycling stability (682 mA h g−1 in the 45th cycle at 200 mA g−1) and an enhanced rate capability (530 mA h g−1 at 1000 mA g−1). NiO–RGONS nanocomposites with a similar structure and RGONS content can also be obtained when the calcinations are performed under air conditions, but they can only keep 292 mA h g−1 and 117 mA h g−1 at 200 mA g−1 and 1000 mA g−1, respectively. The high electrochemical performances of the as-prepared Ni-doped NiO–RGONS nanocomposites could be attributed to their unique structure, in which the highly dispersed Ni NPs have some catalytic effects and improve the electronic conductivity. Also, the layered structure of the NiO nanoplates and RGONSs prevents the aggregation of NiO and decreases the stacking of the RGONSs.
Co-reporter:Yinglin Xiao, Jiantao Zai, Liqi Tao, Bo Li, Qianyan Han, Chao Yu and Xuefeng Qian
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 11) pp:3939-3945
Publication Date(Web):18 Jan 2013
DOI:10.1039/C3CP50220A
MnFe2O4–graphene nanocomposites (MnFe2O4–GNSs) with enhanced electrochemical performances have been successfully prepared through an ultrasonic method, e.g., approximate 1017 mA h g−1 and 767 mA h g−1 reversible capacities are retained even after 90 cycles at a current density of 0.1 A g−1 and 1 A g−1, respectively. The remarkable improvement in the reversible capacity, cyclic stability and rate capability of the obtained MnFe2O4–GNSs nanocomposites can be attributed to the good electrical conductivity and special structure of the graphene nanosheets. On the other hand, MnFe2O4 also plays an important role because it transforms into a nanosized hybrid of Fe3O4–MnO with a particle size of about 20 nm during discharge–charge process, and the in situ formed hybrid of Fe3O4–MnO can be combined with GNSs to form a spongy porous structure. Furthermore, the formed hybrid can also act as the matrix of MnO or Fe3O4 to prevent the aggregation of Fe3O4 or MnO, and accommodate the volume change of the active materials during the discharge–charge processes, which is also beneficial to improve the electrochemical performances of the MnFe2O4–GNSs nanocomposites.
Co-reporter:Jiantao Zai, Hongjin Chen, Chongwen Huang, Jie Huang, Fukun Chen, Miao Xu, Xuefeng Qian
Materials Chemistry and Physics 2013 Volume 143(Issue 1) pp:15-18
Publication Date(Web):16 December 2013
DOI:10.1016/j.matchemphys.2013.08.056
•A conversion of Cu2O nanocrystals into hollow cubic-like CuInS2 cages has been achieved.•The formation of hollow structures could be attributed to the Kirkendall effect.•Ostwald ripening process also plays an important role.•Surfactants are necessary to the formation of these hollow structures.Hollow cubic-like CuInS2 cages were prepared with cubic Cu2O nanocrystals as self-sacrificing template through solvothermal process. The formation of these hollow structures could be attributed to the migration of copper ions and the copy of cubic Cu2O template based on the Kirkendall effect and the Ostwald ripening process. Such process and mechanism might be extended to synthesize other hollow ternary chalcogenide materials.
Co-reporter:Yanping Yuan, Weimin Du and Xuefeng Qian
Journal of Materials Chemistry A 2012 vol. 22(Issue 2) pp:653-659
Publication Date(Web):03 Nov 2011
DOI:10.1039/C1JM13091A
Homogenous ZnxGa2O3+x (0 ≤ x ≤ 1) solid solution nanocrystals were successfully prepared by a solvothermal approach and characterized by X-ray powder diffraction (XRD), X-ray spectra in fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and X-ray photoelectron spectrum (XPS). XRD pattern analysis revealed that the lattice parameters of ZnxGa2O3+x (0 ≤ x ≤ 1) solid solution nanocrystals increased linearly with the increase of ZnGa2O4 ratio according to Vegard's law, which confirmed the homogenous structures of these solid solution nanocrystals. UV-vis absorption spectra demonstrated that the band gap of the obtained ZnxGa2O3+x solid solution nanocrystals could be precisely tuned in the range of 4.43 to 3.70 eV by elaborately controlling the content of zinc. The emission of ZnxGa2O3+x solid solution nanocrystals strengthened and red-shifted gradually with the increase of x value, and ZnGa2O4 nanocrystals showed an intense blue emission. XPS results revealed that ZnxGa2O3+x binding energy of O2− 1s increased with the increase of the x value, indicating the decrease of the oxygen vacancies (Vo*) of Oh sites and the increase of the symmetry of the Ga–O octahedron, which resulted in the emission red-shift of ZnxGa2O3+x solid solution.
Co-reporter:Miao Xu, Jiantao Zai, Yanping Yuan and Xuefeng Qian
Journal of Materials Chemistry A 2012 vol. 22(Issue 45) pp:23929-23934
Publication Date(Web):12 Sep 2012
DOI:10.1039/C2JM35375J
A series of (CuIn)xZn2(1−x)S2 solid solutions has been successfully synthesized by a solvothermal approach, and the obtained solid solutions, with a size of about 10 nm, exhibit significant absorption in the visible light region and their band gap can be correspondingly tuned from 2.59 eV to 1.64 eV with an increase of the x value from 0.05 to 0.5, implying that they can be used as visible-light driven photocatalysts. Furthermore, the obtained (CuIn)xZn2(1−x)S2 solid solutions display highly efficient photocatalytic activities for H2 evolution from aqueous solutions containing sacrificial reagents (SO32− and S2−) under visible light (λ > 420 nm) even without noble metal co-catalysts, e.g. (CuIn)0.2Zn1.6S2, with a band gap of 2.10 eV, exhibits the highest photocatalytic activity of 0.984 mmol g−1 h−1 even without a Pt co-catalyst. Further studies reveal that the photocatalytic H2 evolution of solid solutions depends on their composition as well as the photophysical properties, such as the ability to absorb visible light and the generation and separation of photo-induced electrons and holes.
Co-reporter:Liqi Tao, Jiantao Zai, Kaixue Wang, Haojie Zhang, Miao Xu, Jie Shen, Yuezeng Su, Xuefeng Qian
Journal of Power Sources 2012 Volume 202() pp:230-235
Publication Date(Web):15 March 2012
DOI:10.1016/j.jpowsour.2011.10.131
Co3O4 nanorods/GNS (graphene nanosheets) nanocomposites have been synthesized through a one-spot solvothermal method, and characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. Electrochemical performances reveal that the obtained Co3O4 nanorods/GNS nanocomposites exhibit improved cycling stability, remarkably high reversible lithium storage capacity and superior rate capability, e.g. approximate 1310 mAh g−1 and 1090 mAh g−1 of capacity are retained even after 40 cycles at a current density of 100 mA g−1 and 1000 mA g−1, respectively. The high electrochemical performances can be attributed to the unique structure of Co3O4 nanorods/GNS nanocomposites, in which the 1D structure of Co3O4 can prevent the aggregation of Co3O4 and reduce the stacking degree of GNS, providing an excellent ion diffusion and electronic conduction pathway.Highlights► Co3O4 nanorods/GNS nanocomposites were synthesized by a solvothermal method. ► They exhibited the improved cycling stability and high lithium storage capacity. ► The performances could be attributed to the 1D structure of Co3O4 and the modification of GNS.
Co-reporter:Jiantao Zai, Xuefeng Qian, Kaixue Wang, Chao Yu, Liqi Tao, Yinglin Xiao and Jiesheng Chen
CrystEngComm 2012 vol. 14(Issue 4) pp:1364-1375
Publication Date(Web):05 Dec 2011
DOI:10.1039/C1CE05950E
Three kinds of 3D-hierarchical SnS2 micro/nano-structures were successfully synthesized through a one-pot hydrothermal method by controlling the ratio of SnCl4 and L-cysteine. It was found that these obtained 3D-hierarchical SnS2 structures had great differences in their chemical composition, crystalline property, building blocks, assembling format and porous structure. The formation processes of the hierarchical structures were studied well and the possible mechanisms were also proposed. The lithium storage properties of these 3D-hierarchical SnS2 structures were carefully studied by charge-discharge test and cyclic voltammetry method. The results indicated that the crystalline properties of the electrode materials could influence the initial electrochemical reactivity and the small size of building blocks could greatly improve the reversibility of electrochemical reaction and rate performances. Furthermore, the large surface area, porous structure and free space derived from the 3D hierarchical structures were beneficial to the long-term cycling stability of electrode materials.
Co-reporter:Liqi Tao, Jiantao Zai, Kaixue Wang, Yihang Wan, Haojie Zhang, Chao Yu, Yinglin Xiao and Xuefeng Qian
RSC Advances 2012 vol. 2(Issue 8) pp:3410-3415
Publication Date(Web):28 Feb 2012
DOI:10.1039/C2RA00963C
3D-hierarchical NiO–graphene nanosheet (GNS) composites as high performance anode materials for lithium-ion batteries (LIBs) were synthesized through a simple ultrasonic method, and characterized by X-ray diffraction, Raman spectrum, field emission scanning electron microscopy and transmission electron microscopy. The results show that the 3D-hierarchical NiO carnations with nanoplates as building blocks are homogeneously anchored onto GNS and act as spacers to reduce the stacking of GNS. Electrochemical performances reveal that the obtained 3D-hierarchical NiO–GNS composites exhibit remarkably high reversible lithium storage capacity, good rate capability and improved cycling stability, e.g. approximate 1065 mA h g−1 of reversible capacity is retained even after 50 cycles at a current density of 200 mA g−1. The remarkable improvement of electrochemical performances of the obtained composites could be attributed to the decrease of the volume expansion and contraction of NiO and the improvement of the electronic conductivity of composites during the cycling process.
Co-reporter:Jie Shen, Jiantao Zai, Yanping Yuan, Xuefeng Qian
International Journal of Hydrogen Energy 2012 Volume 37(Issue 22) pp:16986-16993
Publication Date(Web):November 2012
DOI:10.1016/j.ijhydene.2012.08.038
Hexagonal ZnIn2S4 photocatalysts with 3D-hierarchical persimmon-like shape have been successfully synthesized via an oleylamine (OA)-assisted solvothermal method. Hydrogen evolution experiments revealed that the obtained hierarchical ZnIn2S4 possessed good photocatalytic activity, e.g. hydrogen production rate reached to 220.45 μmol h−1 and the quantum yield was up to 13.16% when 3% Pt was loaded. Further delicate tuning the percentage of exposed facet of the obtained ZnIn2S4 crystals, it was found that the increase of {006} facets, terminated by metal ions, would improve their photocatalytic activity, and the relationship between the crystal structure and photocatalytic properties had been studied.Highlights► Persimmon-like ZnIn2S4 microspheres were prepared using an oleylamine-assisted solvothermal method. ► The obtained hierarchical ZnIn2S4 shows great photocatalytic activity. ► ZnIn2S4 samples with different facets exposed were prepared by controlling the reaction time. ► The increase of {006} facets would improve photocatalytic activity of ZnIn2S4.
Co-reporter:Jiantao Zai, Kaixue Wang, Yuezeng Su, Xuefeng Qian, Jiesheng Chen
Journal of Power Sources 2011 Volume 196(Issue 7) pp:3650-3654
Publication Date(Web):1 April 2011
DOI:10.1016/j.jpowsour.2010.12.057
3D hierarchical SnS2 microspheres have been designed and fabricated via a one-pot biomolecule-assisted hydrothermal method. When used as anode material in rechargeable Li-ion batteries, the as-formed SnS2 microspheres self-assembled by layered nanosheets, show high lithium storage capacity, long-term cycling stability and superior rate capability. After charge–discharge for 100 cycles, the remaining discharge capacities are kept as high as 570.3, 486.2, and 264 mAh g−1 at 1C (0.65 A g−1), 5C, and 10C rate, respectively. Such outstanding performance of these SnS2 microspheres is ascribed to their unique 3D hierarchical structures. The new charge–discharge mechanism of 3D SnS2 microsphere as anode in Li-ion battery is further revealed.Research highlights▶ Three-dimensional hierarchical SnS2 spheres were synthesized through a facile one-pot hydrothermal method and showed high lithium storage capacity, long-term cycling stability and superior rate capability. ▶ The high performances are ascribed to their unique 3D hierarchical structures.
Co-reporter:Tianyu Zhao, Jiantao Zai, Miao Xu, Qiong Zou, Yuezeng Su, Kaixue Wang and Xuefeng Qian
CrystEngComm 2011 vol. 13(Issue 12) pp:4010-4017
Publication Date(Web):13 Apr 2011
DOI:10.1039/C1CE05113J
A high-efficiency Bi2O2CO3 photocatalyst was successfully synthesized using tri-sodium citrate as both the coordinating agent and carbon source through a hydrothermal process. Morphology modulation of the obtained products could be easily realized by tuning the concentration of tri-sodium citrate in sponge-like, rose-like and plate-like shapes. The as-prepared sponge-like Bi2O2CO3 microspheres, owning a narrowed band gap of 2.87 eV and a higher BET surface area of 43.99 m2 g−1, exhibit powerful visible-light-photocatalytic activity for the degradation of dyes under 300 W Xe lamp light irradiation. It is worthy to note that the optimal sponge-like Bi2O2CO3 microspheres also possess superior photocatalytic ability under natural sunlight.
Co-reporter:Weimin Du, Dehua Deng, Zhitao Han, Wei Xiao, Cheng Bian and Xuefeng Qian
CrystEngComm 2011 vol. 13(Issue 6) pp:2071-2076
Publication Date(Web):10 Jan 2011
DOI:10.1039/C0CE00596G
Single-crystalline, hexagonal tin disulfide (SnS2) nanoplatelets were successfully synthesized through an improved solvothermal process with SnCl4·5H2O and carbon disulfide (CS2) as precursors. The crystal phase, morphology, and crystal lattice of the prepared products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), respectively. Results reveal that the synthesized SnS2 nanoplatelets are in the hexagonal structure with 20–60 nm in diameter and 7–10 nm in thickness. The structural and HRTEM analysis indicates that the formation of SnS2 nanoplatelets with hexagonal morphology result from the accelerating growth of six energetically equivalent high-index crystalline planes {110} and the retarded growth of {001} crystalline planes. The photocatalytic degradation properties of hexagonal SnS2 nanoplatelets driven by solar light were further investigated with Rhodamine B (RhB) as simulating pollutant. Results show that these SnS2 nanoplatelets have a good performance of photocatalytic degradation on RhB, and the decolorizing rate can reach 97.7% after being irradiated for 70 min by solar light. Better photocatalytic properties indicate that hexagonal SnS2 nanoplatelets are a type of promising photocatalyst driven by solar light and have potentially applied prospects in wastewater treatment and environmental protection.
Co-reporter:Yanping Yuan, Jiantao Zai, Yuezeng Su, Xuefeng Qian
Journal of Solid State Chemistry 2011 Volume 184(Issue 5) pp:1227-1235
Publication Date(Web):May 2011
DOI:10.1016/j.jssc.2011.03.022
Monodispersed AgGaS2 three-dimensional (3D) nanoflowers have been successfully synthesized in a “soft-chemical” system with the mixture of 1-octyl alcohol and cyclohexane as reaction medium and oleylamine as surfactant. The crystal phase, morphology and chemical composition of the as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution TEM (HTEM), respectively. Results reveal that the as-synthesized AgGaS2 nanoflowers are in tetragonal structure with 3D flower-like shape. Controlled experiments demonstrated that the shape transformation of AgGaS2 nanocrystals from 3D nanoflowers (50 nm) to nanoparticles (10–20 nm) could be readily realized by tuning the reaction parameters, e.g., the ratio of octanol to cyclohexane, the length of carbon chain of fatty alcohol, the concentration of oleylamine, etc. The UV–vis and PL spectra of the obtained AgGaS2 nanoflowers and colloids were researched. In addition, the photoelectron energy conversion (SPV) of AgGaS2 nanoflowers was further researched by the surface photovoltage spectra.Graphical abstractVarious AgGaS2 nanocrystals with different morphologies and sizes including 3D nanoflowers (a) and colloids (b) were synthesized in mixed solvent reaction system and their PL spectra was researched (c).Highlights► Ternary chalcogenide AgGaS2 nanocrystals were synthesized in a simple mixed solvent system. ► The shape and size transformation of AgGaS2 from 3D nanoflowers to colloids could be tuned effectively. ► AgGaS2 nanoflowers was obtained with relatively insufficient ligands protection in reaction system, otherwise, AgGaS2 colloids was obtained. ► Provide a new choice to prepare ternary nanomaterials and further understand the reaction mechanisms along with the growth kinetics of ternary nanocrystals.
Co-reporter:Liwu Qian, Jiantao Zai, Zhu Chen, Jun Zhu, Yanping Yuan and Xuefeng Qian
CrystEngComm 2010 vol. 12(Issue 1) pp:199-206
Publication Date(Web):03 Sep 2009
DOI:10.1039/B911401G
Yttrium fluoride such as Na(Y1.5Na0.5)F6 and α-NaYF4; YF3 has been successfully synthesized via a salt-assisted hydrothermal method in the presence of sodium nitrate. The morphology and chemical composition of the as-obtained products can be controlled by monitoring the reaction parameters inclusive of the time-zero concentration of salt solution, reaction temperature and time. The as-prepared products cover Na(Y1.5Na0.5)F6, α-NaYF4 and YF3, while the corresponding morphology changes from spherical aggregation to octahedron, which were characterized by XRD, SEM, and TEM. Moreover, LnF3 (Ln = La, Nd, Eu, Gd) can also be synthesized using the same method. Further studies reveal that the morphology and composition of the as-synthesized lanthanide fluoride can be determined mainly by the ionic radius of rare earth and the concentration of NaNO3. It is emphasized that the sodium nitrate plays an important role in such control of the differentiated products. Apart from these findings, the photoluminescent properties of Eu3+:YF3 octahedral crystals are further investigated.
Co-reporter:Zhu Chen, Liwu Qian, Jun Zhu, Yanping Yuan and Xuefeng Qian
CrystEngComm 2010 vol. 12(Issue 7) pp:2100-2106
Publication Date(Web):27 Jan 2010
DOI:10.1039/B921228K
Three-dimensional (3D) hierarchical Bi2WO6 microspheres were successfully synthesized by a simple inorganic salt-assisted hydrothermal process. Morphology modulation of the obtained products could be easily realized by tuning the concentration of the nitrate. It is worthy to note that the obtained hierarchical Bi2WO6 microspheres exhibit powerful visible-light-photocatalytic activity for the degradation of Rhodamine-B (RhB) under 300 W Xe lamp light irradiation. A possible salt-assisted formation mechanism was proposed on the basis of the experimental results. Furthermore, this work might represent a novel synthesis strategy for other photocatalysts with desired photocatalytic activity.
Co-reporter:Jun Zhu, Xuefeng Qian
Journal of Solid State Chemistry 2010 Volume 183(Issue 7) pp:1632-1639
Publication Date(Web):July 2010
DOI:10.1016/j.jssc.2010.05.015
CuO hierarchical hollow nanostructures, assembled by nanosheets, were successfully prepared in n-octanol/aqueous liquid system through a microwave approach. Controlled experiments revealed that both bubble and interface play key roles in determining the self-assembly process of CuO hierarchical hollow nanostructures, and the morphology/size of building blocks and final products could be readily tuned by adjusting reaction parameters. Furthermore, a self-assembly mechanism of aggregation-then-growth process through bubble template was proposed for the formation of the hollow hierarchical architectures. Photocatalytic performance evidenced that the obtained CuO hierarchical hollow nanostructures possessed superior photocatalytic efficiency on RhB than that of non-hollow nanostructures, which could be easily demonstrated by SPS response about the separation and recombination situation of photogenerated charges.From 2-D CuO nanosheets to 3-D hollow nanospheres: interface-assisted synthesis, surface photovoltage properties and photocatalytic activity. Various CuO architectures with different morphologies and sizes, including hierarchical hollow nanostructures were prepared through a synergic bubble-template and interface-assisted approach.
Co-reporter:Jun Zhu, Xuefeng Qian
Solid State Sciences 2010 Volume 12(Issue 8) pp:1314-1322
Publication Date(Web):August 2010
DOI:10.1016/j.solidstatesciences.2010.04.032
Assembled ZnQ2·2H2O microstructures, such as microsheet, sandwich-like structure and hexangular microflake, have been successfully prepared in CTAB microemulsion system through the stacking of ZnQ2·2H2O molecules and oriented aggregation of ZnQ2·2H2O original building blocks. Controlled experiments demonstrated that the morphologies of building block and final product could be readily tuned by reaction parameters, and a formation mechanism, involving re-precipitation, growth and oriented aggregation process, has been proposed on the basis of time-dependent experimental results. The obtained products were carefully characterized by X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), transmission electron microscope (TEM), field-emission scanning electron microscope (FESEM), FT-IR spectrum, UV–vis spectrum and photoluminescence (PL) spectrum. The surface photovoltage (SPV) of the obtained ZnQ2·2H2O microstructures was investigated by means of surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (FISPS). The SPS and FISPS revealed that the photogenerated charges of ZnQ2·2H2O could be separated distinctly and ZnQ2·2H2O possessed p-type semiconductor characteristics, respectively. Furthermore, UV–vis and PL spectra evidenced the optical properties of ZnQ2·2H2O were sensitive to its microstructure or morphology.
Co-reporter:Liwu Qian, Jun Zhu, Weimin Du, Xuefeng Qian
Materials Chemistry and Physics 2009 Volume 115(2–3) pp:835-840
Publication Date(Web):15 June 2009
DOI:10.1016/j.matchemphys.2009.02.047
Cubic-like CeO2 nanocrystals were successfully synthesized through an improved-toluene solvothermal process using hexadecylamine (HAD) as a capping agent and CeCl3·7H2O as a precursor at 180 °C for 24 h. These nanocubes are about 10 nm in size, and have a tendency to assemble into 2D superstructure. The obtained samples were characterized by means of X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). It was found that the water content, the concentration of ligand and kinds of aliphatic amine played important roles in the formation of the novel morphology. A possible formation mechanism was proposed based on the controlling reaction parameters. The electrochemical and photocatalytic properties of the as-synthesized samples exhibited the size/shape-dependent properties and potential applications.
Co-reporter:Liwu Qian, Weiming Du, Qiang Gong, Xuefeng Qian
Materials Chemistry and Physics 2009 Volume 114(Issue 1) pp:479-484
Publication Date(Web):15 March 2009
DOI:10.1016/j.matchemphys.2008.09.062
LnPO4·nH2O (Ln = La, Ce, Pr, Nd, Sm, Eu and Gd) (n = 0–1) nanowires are synthesized without using any surfactants or templates at room temperature. The as-obtained nanowires are within 10–50 nm in diameter and up to 10 μm in length. The most important improvement is that the aspect ratios of LnPO4·nH2O nanowires can be effectively controlled by adjusting the reaction time and pH value of the reaction system. The as-synthesized nanowires are characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It is interesting to find that both the inherent crystal structure of light lanthanide phosphate and the anisotropic growth affect the formation of these nanowires. Under the similar reaction conditions, the Eu3+-doped LaPO4 nanomaterials are also synthesized as a comparison. The photoluminescence (PL) instrument is used to investigate the optical properties of the doped nanomaterials.
Co-reporter:Liwu Qian, Yicai Gui, Shuai Guo, Qiang Gong, Xuefeng Qian
Journal of Physics and Chemistry of Solids 2009 Volume 70(3–4) pp:688-693
Publication Date(Web):March–April 2009
DOI:10.1016/j.jpcs.2009.02.005
Ln(OH)3 (Ln=La, Pr, Nd, Sm, Eu, Gd) nanorods are synthesized without using any surfactants or templates at room temperature. The as-obtained nanorods are within 4–25 nm in diameter and up to 200 nm in length. The most important improvement is that the aspect ratio of the obtained nanorods can be effectively controlled by adjusting the reaction time and pH value of the reaction system. The as-synthesized nanorods are characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). It is interesting to find that both the inherent crystal structure of light lanthanide hydroxide and the chemical potential affect the formation of nanorods. The photoluminescence (PL) instrument is used to investigate the optical properties of the Eu(OH)3 nanorods and its abnormal luminescence behaviors are observed.
Co-reporter:Z. Chen, Q. Gong, J. Zhu, Y.P. Yuan, L.W. Qian, X.F. Qian
Materials Research Bulletin 2009 44(1) pp: 45-50
Publication Date(Web):
DOI:10.1016/j.materresbull.2008.04.008
Co-reporter:Liwu Qian Dr.;Jun Zhu Dr.;Zhu Chen;Yicai Gui;Qiang Gong Dr.;Yanping Yuan Dr.;Jiantao Zai Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 5) pp:1233-1240
Publication Date(Web):
DOI:10.1002/chem.200801724
Abstract
Nearly monodisperse YVO4 architectures with persimmon-like, cube-like and nanoparticle shapes have been synthesised on a large scale by means of a complexing-agent-assisted solution route. The shape and size of these as-prepared architectures can be tuned effectively by controlling the reaction conditions, such as reaction time, the molar ratio of complexing agent/Y3+ and different complexing agents. As a typical morphology, the growth process of monodisperse nanopersimmons has been examined. To extend this method, other LnVO4 (Ln=Ce, Gd, Dy, Er) complexes with well-defined shape and dimensionality can also be achieved by adjusting different rare earth precursors. Further studies reveal that the morphology of the as-synthesised lanthanide orthovanadate is determined mainly by the interaction between rare earth ion and the complexing agent. Ultraviolet (UV) absorption and photoluminescence spectra show that the optical properties of YVO4 nanopersimmons are relevant to their size and shape. This work sheds some light on the design of well-defined complex nanostructures, and explores the potential applications of the as-synthesised architectures.
Co-reporter:Weimin Du, Jun Zhu, Shixiong Li and Xuefeng Qian
Crystal Growth & Design 2008 Volume 8(Issue 7) pp:2130
Publication Date(Web):June 12, 2008
DOI:10.1021/cg7009258
Ultrathin β-In2S3 nanobelts have been successfully synthesized via a facile improved solvothermal route. The crystal phase, morphology, crystal lattice and composition of as-prepared products were characterized by XRD, FESEM, TEM, HRTEM and EDS, respectively. Results revealed that the as-synthesized β-In2S3 nanobelts are in cubic structure 50−90 nm in width, 13 ± 2 nm in thickness, and the overall length even up to several microns. A possible shape evolution and crystal growth mechanism was suggested, and the formation of β-In2S3 nanobelts resulted from the preferential growth along the ⟨220⟩ direction and enclosed by {202} and {022̅} crystallographic facets. The strong quantum confinement effect in UV−vis spectra and the blue emission in photoluminescence spectra imply the as-synthesized β-In2S3 nanobelts as a promising candidate for phosphor in display devices. Furthermore, the good photocatalytic effects indicate that these β-In2S3 nanobelts are likely to be applied as a new kind of photocatalyst in the future.
Co-reporter:Weimin Du, Xuefeng Qian, Xinshu Niu and Qiang Gong
Crystal Growth & Design 2007 Volume 7(Issue 12) pp:2733
Publication Date(Web):November 15, 2007
DOI:10.1021/cg070088t
Nickel diselenide nanocrystals in well-defined star shape have been successfully synthesized via an improved solvothermal route with oleic acid as a capping ligand. The obtained products were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and energy-dispersive X-ray analysis (EDS). Results revealed that cubic NiSe2 nanocrystals were in a star-like shape and each nanostar consisted of a central core and six symmetrical horns in which the length of each horn was about 85 nm, the diameter of central core was about 90 nm, and the overall length between two most distance vertices was about 260 nm. Based on the HR-TEM analysis and the reaction process, an oriented attachment growth mechanism was suggested for the formation of six-horn star-like NiSe2, which resulted from the attachment growth of primary building particles along six ⟨100⟩ directions. Controlled experiments further demonstrated that the star-like shape of NiSe2 nanocrystals was controlled by the cooperative effects of precursor, solvent, and capping regents.
Co-reporter:Weimin Du Dr. ;Xiaodong Ma Dr.;Qiang Gong Dr.;Hongliang Cao Dr.;Jie Yin
Chemistry - A European Journal 2007 Volume 13(Issue 11) pp:
Publication Date(Web):2 JAN 2007
DOI:10.1002/chem.200601368
Single-crystalline, hexagonal covellite (CuS) nanoplatelets were successfully synthesized through a facile, inexpensive, reproducible, and improved solvothermal process in toluene at 120 °C for 24 h with hexadecylamine as a capping agent and copper acetate and carbon disulfide as precursors. These nanoplatelets are about 26±1.5 nm in diameter and 8±1.2 nm thick, and have a tendency to self-assemble into pillarlike nanostructures with face-to-face stacks, raftlike nanostructures with side-by-side arrays, and stratiform nanostructures with layer-by-layer self-assembly. The crystal shape, morphology, and crystallographic orientation of the covellite obtained were investigated by means of XRD, TEM, and high-resolution TEM, and a potential self-assembly mechanism was proposed.
Co-reporter:Weimin Du Dr. ;Jie Yin ;Qiang Gong Dr.
Chemistry - A European Journal 2007 Volume 13(Issue 31) pp:
Publication Date(Web):26 JUL 2007
DOI:10.1002/chem.200700618
Colloidal, monodisperse, single-crystalline pyramidal CuInS2 and rectangular AgInS2 nanocrystals were successfully synthesized through a convenient and improved solvothermal process that uses hexadecylamine as a capping reagent. The crystal phase, morphology, crystal lattice, and chemical composition of the as-prepared products were characterized by using X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, and energy dispersive X-ray spectroscopy. Results revealed that the as-synthesized CuInS2 colloid is in the tetragonal phase (size: 13–17 nm) and the AgInS2 in the orthorhombic structure (size: 17±0.5 nm). A possible shape evolution and crystal growth mechanism has been suggested for the formation of pyramidal CuInS2 and rectangular AgInS2 colloids. Control experiments indicated that the morphology- and/or phase-change of CuInS2 and orthorhombic AgInS2 colloids are temperature- and/or time-dependent. CuInS2 colloids absorb well in the range of visible light at room-temperature, indicating its potential application as a solar absorber. Two photoluminescence (PL) subbands at 1.938 and 2.384 eV in the PL spectra of CuInS2 colloids revealed that the recombination of the closest and the second closest donor–acceptor pairs within the CuInS2 lattice, in which the donor defect (Cui) occupies an interstitial position and the acceptor defect (VIn) resides at an adjacent cation site. In addition, the synthesis strategy developed in this study is convenient and inexpensive, and could also be used as a general process for the synthesis of other pure or doped ternary chalcogenides that require a controlled size (or shape). This process could be extended to the synthesis of other functional nanomaterials.
Co-reporter:Hongliang Cao, Xuefeng Qian, Jiantao Zai, Jie Yin and Zikang Zhu
Chemical Communications 2006 (Issue 43) pp:4548-4550
Publication Date(Web):20 Sep 2006
DOI:10.1039/B609848G
With the use of PVP (polyvinylpyrrolidone) as capping reagent, cubic, octahedral and spherical Cu2O nanocrystals were obtained in aqueous media when different reducing agents were applied. After adding selenium sources at room temperature, these nanocrystals could be converted (based on the Kirkendall effect) into hollow Cu2−xSe nanocages that keep their corresponding orignial morphologies.
Co-reporter:Qiang Gong, Gang Li, Xuefeng Qian, Hongliang Cao, Weimin Du, Xiaodong Ma
Journal of Colloid and Interface Science 2006 Volume 304(Issue 2) pp:408-412
Publication Date(Web):15 December 2006
DOI:10.1016/j.jcis.2006.09.050
The single crystal octahedra of tetragonal CdMoO4 were synthesized on large scale via a microemulsion-mediated hydrothermal route at 120 °C for 10 h. The structures, compositions and morphologies of the as-prepared products were characterized by X-ray power diffraction pattern, field emission scanning electronic microscopy, transmission electron microscopy. Further studies reveal that the octahedral CdMoO4 crystal has eight equivalent exposed crystal faces {101}{101}. The possible growth mechanism of the CdMoO4 octahedral is based on the anisotropic growth habit of CdMoO4 crystals and the selective absorption of surfactant molecules CTAB on the faces of the prime crystals, and the reaction time, composition of the microemulsions and temperature have considerable effects on the final morphology of CdMoO4.Large scale of monodisperse single crystal CdMoO4 octahedral microparticles has been prepared via a microemulsion-mediated hydrothermal procedure.
Co-reporter:Wei Zeng, Xue-Feng Qian, Jie Yin, Zi-Kang Zhu
Materials Chemistry and Physics 2006 Volume 97(2–3) pp:437-441
Publication Date(Web):10 June 2006
DOI:10.1016/j.matchemphys.2005.08.040
The functional MCM-41 materials were prepared through co-condensation method, as compared postsynthesis and solvothermal processes were also used. The as-functionalized MCM-41 materials have been characterized by XRD, TEM, N2 adsorption and 29Si CP/MAS NMR. The modified materials have been used as drug-controlled delivery system of aspirin. The results showed that the release properties of this system were affected by functionalization degree and the distribution of functional groups on the pore wall surface of mesoporous materials, and the better delivery rate of MCM-41 materials would be obtained via co-condensation process.
Co-reporter:Zhi Li, Xue-feng Qian, Jie Yin, Zi-kang Zhu
Journal of Solid State Chemistry 2005 Volume 178(Issue 6) pp:1765-1772
Publication Date(Web):June 2005
DOI:10.1016/j.jssc.2005.03.033
Gold tubes membrane with novel morphology was fabricated on glass substrate by electroless plating gold on ZnO crystals array, and then annealing and removing the ZnO template by acid erosion. The morphology and size of the gold tubes membrane were decided by ZnO template. Hexagonal gold tubes membrane and double-wall gold tubes membrane were obtained, which enjoys some potential usage in electrode modification or chemical separation due to their huge surface area and unique geometric structure. SEM images show that those gold tubes in membrane are hollowed hexagonal columns with a closed head and an open bottom. Further researches found that two main factors determined the success of replication: the gold seeds (4–5 nm in diameter) immobilized on ZnO surface through APTMS (3-Aminopropyl-trimethoxysilane) before gold electroless plating and the annealing condition after electroless plating.Utilizing ZnO template with different morphologies, rods array and tubes array, we got the hexagonal tubes membrane and double-wall tubes membrane which enjoy a potential usage as electrodes material or chemical separation membrane due to their novel geometrical shape or huge surface area.
Co-reporter:Hua-Feng Shao, Xue-Feng Qian, Zi-Kang Zhu
Journal of Solid State Chemistry 2005 Volume 178(Issue 11) pp:3522-3528
Publication Date(Web):November 2005
DOI:10.1016/j.jssc.2005.09.007
ZnS hollow nanospheres with nanoporous shell were successfully synthesized through the evolvement of ZnO nanospheres which were synthesized by hydrothermal method with poly (sodium-p-styrene sulfonate) (PSS) as surfactant at low temperature. The as-synthesized samples were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), UV/vis spectrum and N2 adsorption. The results showed that the shell of as-synthesized ZnS hollow structure was composed of many fine crystallites and had a nanoporous structure with pore diameter about 4 nm demonstrated by N2 adsorption/desorption isotherm. The sample possessed efficiency of photocatalytic degradation on X-containing (X=Cl, Br, I) organic pollutants.Nitrogen adsorption/desorption isotherm and Brunauer–Emmett–Teller (BET) pore-size distribution plot (inset) of ZnS hollow spheres.
Co-reporter:Zhuo Wang, Xue-feng Qian, Yi Li, Jie Yin, Zi-kang Zhu
Journal of Solid State Chemistry 2005 Volume 178(Issue 5) pp:1589-1594
Publication Date(Web):May 2005
DOI:10.1016/j.jssc.2004.08.032
Arrayed structures are desirable for many applications, but the fabrication of many material arrays remains a significant challenge. As a prominent II–VI semiconductor, large-scale arrayed ZnS structure has not been easily fabricated. Here, we introduce a simple structure conversion route for the synthesis of novel arrayed structures, and large-scale tube-like ZnS structure arrays and cable-like ZnS–ZnO composite arrays were successfully prepared through sulfuration conversion from arrayed rod-like ZnO structure based on a hydrothermal method at low temperature. XRD, EDS, SEM, TEM and PL are used to confirm the formation of the novel arrayed structure and trace the conversion process. The results show that the conversion ratio can be conveniently tailored by the reaction time, and the PL properties of the obtained materials can be adjusted through the conversion ratio. Especially, the cable-like structure holds the PL properties of both ZnO and ZnS structures. This simple solution method can be further extended to the preparation of other semiconductor sulfide and selenide, and can amplify the application field of large-scale arrays of semiconductors.
Co-reporter:Hua-Feng Shao, Xue-Feng Qian, Jie Yin, Zi-Kang Zhu
Journal of Solid State Chemistry 2005 Volume 178(Issue 10) pp:3130-3136
Publication Date(Web):October 2005
DOI:10.1016/j.jssc.2005.07.011
The hexagram and arrayed β-FeOOH nanorods were first synthesized free of surfactants through the solvent-thermal method. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectrum (EDAX) and thermal gravimetric analysis (TGA) were used to characterize the as-prepared products. The TEM and FESEM images showed that hexagram β-FeOOH and arrayed rod-like β-FeOOH with an average diameter of 10–15 nm and an average length of 100 nm (aspect ratio is about 10) were prepared. Electrochemical tests show that these nanorods deliver a large discharge capacity of 277 mA h g−1 versus Li metal at 0.1 mA cm−2 (voltage at 1.5–4.2 V). Treated the as-synthesized rod-like β-FeOOH by annealing, rhombus hematite was obtained.The TEM images of the as-synthesized sample II.
Co-reporter:Wei Zeng, Xue-Feng Qian, Yan-Bo Zhang, Jie Yin, Zi-Kang Zhu
Materials Research Bulletin 2005 Volume 40(Issue 5) pp:766-772
Publication Date(Web):18 May 2005
DOI:10.1016/j.materresbull.2005.02.011
MCM-41 materials modified by organic aminopropyl groups have been successfully prepared through solvothermal process and have been used as drug-controlled delivery system of aspirin. The results show that the releasing properties of this delivery system are affected by the amount of aminopropyl groups on the pore wall and the ordered structure of mesoporous materials. These materials were characterized by XRD, TG, FT-IR, TEM, UV and N2 adsorption.Aspirin % release from MCM-41, 3A-6 and 3A-10.
Co-reporter:Yan-Bo Zhang, Xue-Feng Qian, Zhong-Kai Li, Jie Yin, Zi-Kang Zhu
Journal of Solid State Chemistry 2004 Volume 177(Issue 3) pp:844-848
Publication Date(Web):March 2004
DOI:10.1016/j.jssc.2003.09.018
Novel spherical mesoporous silica materials with uniform diameters and starburst mesopore structures were synthesized by a simple one-step procedure with ethanol as the co-solvent in dilute aqueous solution and their formation mechanism was proposed. The arrangement of the pore canal and the diameter of the sphere could be tailored by altering the concentration of ethanol.
Co-reporter:Zhuo Wang, Xue-feng Qian, Jie Yin, Zi-kang Zhu
Journal of Solid State Chemistry 2004 Volume 177(Issue 6) pp:2144-2149
Publication Date(Web):June 2004
DOI:10.1016/j.jssc.2003.10.026
Two-dimensional (2D) arrays of obelisk-like zinc oxide nanorods were successfully synthesized with high efficiency on quartz and glass substrate on a large scale through a simple aqueous solution deposition method with zinc nitrate, ammonia, and ammonium chloride as the precursors. Characterized by XRD, EDS, TEM and SEM, the as-grown zinc oxide rods had a single crystalline obelisk-like hexagonal wurtzite structure with diameters of about 300–400 nm and length up to 5 μm. Both XRD and SEM studies revealed the orientation of ZnO rods, and the orientation of ZnO rods can be controlled easily by temperature, pH of the reaction system and the concentration of reactants.
Co-reporter:Jiantao Zai, Fenglei Cao, Na Liang, Ke Yu, Yuan Tian, Huai Sun, Xuefeng Qian
Journal of Hazardous Materials (5 January 2017) Volume 321() pp:464-472
Publication Date(Web):5 January 2017
DOI:10.1016/j.jhazmat.2016.09.034
•DFT reveals I− can partially substitute CO32−to narrow the bandgap of Bi2O2CO3.•Sodium citrate play a key role on the formation of rose-like I-doped Bi2O2CO3.•Rose-like I-doped Bi2O2CO3 show enhanced visible light response.•The catalyst has enhanced photocatalytic activity to organic and Cr(VI) pollutes.Based on the crystal structure and the DFT calculation of Bi2O2CO3, I− can partly replace the CO32−in Bi2O2CO3 to narrow its bandgap and to enhance its visible light absorption. With this in mind, rose-like I-doped Bi2O2CO3 microspheres were prepared via a hydrothermal process. This method can also be extended to synthesize rose-like Cl- or Br-doped Bi2O2CO3 microspheres. Photoelectrochemical test supports the DFT calculation result that I- doping narrows the bandgap of Bi2O2CO3 by forming two intermediate levels in its forbidden band. Further study reveals that I-doped Bi2O2CO3 microspheres with optimized composition exhibit the best photocatalytic activity. Rhodamine B can be completely degraded within 6 min and about 90% of Cr(VI) can be reduced after 25 min under the irradiation of visible light (λ > 400 nm).Download high-res image (149KB)Download full-size image
Co-reporter:Miao Xu, Jiantao Zai, Yanping Yuan and Xuefeng Qian
Journal of Materials Chemistry A 2012 - vol. 22(Issue 45) pp:NaN23934-23934
Publication Date(Web):2012/09/12
DOI:10.1039/C2JM35375J
A series of (CuIn)xZn2(1−x)S2 solid solutions has been successfully synthesized by a solvothermal approach, and the obtained solid solutions, with a size of about 10 nm, exhibit significant absorption in the visible light region and their band gap can be correspondingly tuned from 2.59 eV to 1.64 eV with an increase of the x value from 0.05 to 0.5, implying that they can be used as visible-light driven photocatalysts. Furthermore, the obtained (CuIn)xZn2(1−x)S2 solid solutions display highly efficient photocatalytic activities for H2 evolution from aqueous solutions containing sacrificial reagents (SO32− and S2−) under visible light (λ > 420 nm) even without noble metal co-catalysts, e.g. (CuIn)0.2Zn1.6S2, with a band gap of 2.10 eV, exhibits the highest photocatalytic activity of 0.984 mmol g−1 h−1 even without a Pt co-catalyst. Further studies reveal that the photocatalytic H2 evolution of solid solutions depends on their composition as well as the photophysical properties, such as the ability to absorb visible light and the generation and separation of photo-induced electrons and holes.
Co-reporter:Min Wang, Jiantao Zai, Bo Li, Yan Wang, Shoushuang Huang, Qingquan He and Xuefeng Qian
Journal of Materials Chemistry A 2016 - vol. 4(Issue 13) pp:NaN4796-4796
Publication Date(Web):2016/03/01
DOI:10.1039/C6TA00184J
Hierarchical Cu2−XSe nanotubes, constructed by nanosheets with a thickness of two unit cells (1.2 nm), have been fabricated with Cu(OH)2 nanorod arrays as self-sacrificial templates at room temperature, with a high surface area of 72.3 m2 g−1. The unique structure of the Cu2−XSe nanotubes leads to high electrocatalytic activity towards the reduction of polysulfides, given their enlarged active surface area, rapid transportation of electrons and mass. As a result, quantum dot-sensitized solar cells (QDSSCs) with the obtained Cu2−XSe nanotubes as the counter electrode material exhibit long-term stability and a high power conversion efficiency of 5.14% (1 sun irradiation simulation), better than those of the commonly-used Cu2S/brass (3.38%) and reference Pt (1.78%) electrodes.
Co-reporter:Fukun Chen, Jiantao Zai, Miao Xu and Xuefeng Qian
Journal of Materials Chemistry A 2013 - vol. 1(Issue 13) pp:NaN4323-4323
Publication Date(Web):2013/01/21
DOI:10.1039/C3TA01491F
3D-hierarchical Cu3SnS4 flowerlike microspheres have been successfully synthesized through a solvothermal process. The reaction temperature and the dosage of the sulfur source play significant roles in the growth of Cu3SnS4 flowerlike microspheres. The formation process of the hierarchical microspheres is studied well and a possible mechanism is also proposed. UV-visible absorption spectra show that the as-synthesized Cu3SnS4 microspheres with a direct band gap of 1.38 eV have stronger absorption from the UV to near-IR region. Further studies reveal that the obtained Cu3SnS4 photocatalysts without any loadings exhibit good photocatalytic activity, and the rate of H2 evolution is determined to be 1.1 mmol h−1 g−1 under simulated solar irradiation.
Co-reporter:Minmin Zhang, Jiantao Zai, Jie Liu, Ming Chen, Zeren Wang, Guan Li, Xuefeng Qian, Liwu Qian and Xibin Yu
Dalton Transactions 2017 - vol. 46(Issue 29) pp:NaN9516-9516
Publication Date(Web):2017/06/27
DOI:10.1039/C7DT01511A
Transition metal sulfides are a kind of potential candidates for efficient and stable CE materials in DSSCs due to their good electrocatalytic ability and stability towards I3− reduction. However, the low conductivity of sulfides is harmful for the electron collection and transfer process, and the absorption/desorption and diffusion process of I−/I3− should be optimized to achieve high electrocatalytic activity over Pt. Herein, a hierarchical CoFeS2/reduced graphene oxide (CoFeS2/rGO) composite was rationally designed and prepared via the in situ conversion of CoFe layer double hydroxide anchored on rGO. Due to the synergistic effects of Co and Fe, unique 3D hierarchical structures formed by nanosheets, and the conductivity of rGO, the CoFeS2/rGO CEs exhibited good electrocatalytic activity and stability towards the reduction of I3− to I−, and the DSSCs could also achieve a high efficiency of 8.82%, higher than those of the devices based on Pt (8.40%) and pure CoFeS2 (8.30%) CEs. Moreover, the devices also showed the characteristics of fast activity onset, good stability, and high multiple start/stop capability. The results indicated that the developed CoFeS2/rGO composite could be a promising alternative for Pt in DSSCs.
Co-reporter:Yuanyuan Liu, Jiantao Zai, Xiaomin Li, Zi-feng Ma and Xuefeng Qian
Dalton Transactions 2017 - vol. 46(Issue 4) pp:NaN1265-1265
Publication Date(Web):2016/12/20
DOI:10.1039/C6DT04467K
Transition metal sulfides with high specific capacity have received increasing research interest in lithium storage. However, the low reversibility of metal sulfides usually leads to the oxidation of Li2S into polysulfides. The dissolution of polysulfides will suppress the regeneration of sulfides due to the loss of Li2S, which usually leads to poor cycling stability of sulfides. Herein, Al2O3 coated Ni3S4 nanoparticles (Ni3S4@Al2O3) have been rationally designed and fabricated via a one-pot hydrothermal process. The regeneration of nickel sulfides, which is the key to cycling stability of sulfides, can be promoted by the localized conversion from metal to metal sulfides because the Al2O3 layer can prevent the diffusion and dissolution of polysulfides. The conversion of Al2O3 to ion-conductive AlF3 can enhance the quick charge transfer process of the lithium ion insertion/extraction reaction. Furthermore, the Al2O3/AlF3 layer can also prevent the growth and aggregation of Ni3S4 nanoparticles to retain the structure of the electrodes during the cycling process. The as-prepared Ni3S4@Al2O3 exhibits a high reversible capacity of 651 mA h g−1 at 500 mA g−1 even after 400 cycles. This method can also be extended to other metal sulfides for improving electrochemical performances.
Co-reporter:Yinglin Xiao, Jiantao Zai, Liqi Tao, Bo Li, Qianyan Han, Chao Yu and Xuefeng Qian
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 11) pp:NaN3945-3945
Publication Date(Web):2013/01/18
DOI:10.1039/C3CP50220A
MnFe2O4–graphene nanocomposites (MnFe2O4–GNSs) with enhanced electrochemical performances have been successfully prepared through an ultrasonic method, e.g., approximate 1017 mA h g−1 and 767 mA h g−1 reversible capacities are retained even after 90 cycles at a current density of 0.1 A g−1 and 1 A g−1, respectively. The remarkable improvement in the reversible capacity, cyclic stability and rate capability of the obtained MnFe2O4–GNSs nanocomposites can be attributed to the good electrical conductivity and special structure of the graphene nanosheets. On the other hand, MnFe2O4 also plays an important role because it transforms into a nanosized hybrid of Fe3O4–MnO with a particle size of about 20 nm during discharge–charge process, and the in situ formed hybrid of Fe3O4–MnO can be combined with GNSs to form a spongy porous structure. Furthermore, the formed hybrid can also act as the matrix of MnO or Fe3O4 to prevent the aggregation of Fe3O4 or MnO, and accommodate the volume change of the active materials during the discharge–charge processes, which is also beneficial to improve the electrochemical performances of the MnFe2O4–GNSs nanocomposites.
Co-reporter:Shoushuang Huang, Qingquan He, Jiantao Zai, Min Wang, Xiaomin Li, Bo Li and Xuefeng Qian
Chemical Communications 2015 - vol. 51(Issue 43) pp:NaN8953-8953
Publication Date(Web):2015/04/21
DOI:10.1039/C5CC02584B
Metastable wurtzstannite Cu2ZnGeS4 (CZGS) nanocrystals were synthesized via a hot-injection method and then used as matrixes to fabricate PtCo–CZGS heterostructured nano-particles. The formed Mott–Schottky heterojunctions in the hybrid nanocrystals promote the transfer of electrons from semiconducting CZGS to metallic PtCo, which accelerates the reduction of I3− to I− in dye-sensitized solar cells.
Co-reporter:Yanping Yuan, Weimin Du and Xuefeng Qian
Journal of Materials Chemistry A 2012 - vol. 22(Issue 2) pp:NaN659-659
Publication Date(Web):2011/11/03
DOI:10.1039/C1JM13091A
Homogenous ZnxGa2O3+x (0 ≤ x ≤ 1) solid solution nanocrystals were successfully prepared by a solvothermal approach and characterized by X-ray powder diffraction (XRD), X-ray spectra in fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and X-ray photoelectron spectrum (XPS). XRD pattern analysis revealed that the lattice parameters of ZnxGa2O3+x (0 ≤ x ≤ 1) solid solution nanocrystals increased linearly with the increase of ZnGa2O4 ratio according to Vegard's law, which confirmed the homogenous structures of these solid solution nanocrystals. UV-vis absorption spectra demonstrated that the band gap of the obtained ZnxGa2O3+x solid solution nanocrystals could be precisely tuned in the range of 4.43 to 3.70 eV by elaborately controlling the content of zinc. The emission of ZnxGa2O3+x solid solution nanocrystals strengthened and red-shifted gradually with the increase of x value, and ZnGa2O4 nanocrystals showed an intense blue emission. XPS results revealed that ZnxGa2O3+x binding energy of O2− 1s increased with the increase of the x value, indicating the decrease of the oxygen vacancies (Vo*) of Oh sites and the increase of the symmetry of the Ga–O octahedron, which resulted in the emission red-shift of ZnxGa2O3+x solid solution.
Co-reporter:Na Liang, Jiantao Zai, Miao Xu, Qi Zhu, Xiao Wei and Xuefeng Qian
Journal of Materials Chemistry A 2014 - vol. 2(Issue 12) pp:NaN4216-4216
Publication Date(Web):2013/12/20
DOI:10.1039/C3TA13931J
Novel Bi2S3/Bi2O2CO3 heterojunction photocatalysts were prepared by a simple chemical reaction from commercial Bi2O2CO3. The photocatalytic activities of Bi2S3/Bi2O2CO3 were evaluated by degrading Rhodamine B (RhB) under visible light and sunlight irradiation. Further investigation revealed that the content of loading bismuth sulfide (Bi2S3) had important effects on the photocatalytic activity of the Bi2S3/Bi2O2CO3 heterojunctions, and the 5 mol% Bi2S3/Bi2O2CO3 heterojunction photocatalyst exhibited the best photocatalytic activity (30 min under visible light, λ > 400 nm). The high photocatalytic activity could be attributed to its good visible light absorption, facilitated charge separation of photogenerated electron–hole pairs and efficient charge transfer path in the partly exposed core in the heterojunctions. These benefits are derived from the unique band gap structure of the Bi2S3/Bi2O2CO3 n–n-type heterojunctions and special morphology with the partly exposed core, which was confirmed by photoluminescent spectra, surface photovoltage spectra and photoelectrochemical characterizations.
