Co-reporter:Qiuyang Ma, Wanwan Wang, Peiyuan Zeng, and Zhen Fang
Langmuir 2017 Volume 33(Issue 9) pp:
Publication Date(Web):February 14, 2017
DOI:10.1021/acs.langmuir.6b04444
A Ge/C spongelike composite is prepared by the facile and scalable single-step pyrolysis of the GeOx/ethylenediamine gel process, which has a feature with three-dimensional interconnected pore structures and is hybridized with nitrogen-doped carbon. A detailed investigation shows that the pore in the sponge is formed for the departure of the gaseous products at the evaluated temperature. As an anode for lithium ion batteries, the obtained composite exhibits superior specific capacity in excess of 1016 mA h g–1 at 100 mA g–1 after 100 cycles. Moreover, the amorphous Ge/C sponge electrode also has a good rate capacity and stable cycling performance. The obtained amorphous Ge/C sponges are a good candidate anode for next-generation lithium ion batteries.
Co-reporter:Qiuyang Ma, Ming Ye, Peiyuan Zeng, Xiaoxiao Wang, Baoyou Geng and Zhen Fang
RSC Advances 2016 vol. 6(Issue 19) pp:15952-15959
Publication Date(Web):29 Jan 2016
DOI:10.1039/C5RA23885D
Amorphous GeOx hollow spheres with uniform particle size were prepared via a soft-template strategy using H2 bubbles as templates. The diameter of the hollow spheres can be controlled by using a micromolecular organic amine, and averages at 142 nm with a shell thickness of about 20 nm. The X-ray photoelectron spectroscopy data showed that the Ge:O stoichiometry ratio is 1:1.25. In the voltage window of 0.01–1.8 V, the discharge capacity of the amorphous GeOx hollow sphere was approximately 794 mA h g−1 at 500 mA g−1 after 100 cycles, demonstrating an excellent capacity retention and stability. In addition, even at different high current rates (2C, 4C), high specific capacities (857, 724 mA h g−1, respectively) can be achieved. The superior electrochemical performance of amorphous GeOx hollow spheres could be attributed to their unique porous hollow nanostructure and homogeneous particle size distribution, which not only enhance the specific capacity, but also alleviate the pulverization problems that prevent particle aggregation and facilitate better rate capabilities.
Co-reporter:Peiyuan Zeng, Xiaoxiao Wang, Ming Ye, Qiuyang Ma, Jianwen Li, Wanwan Wang, Baoyou Geng and Zhen Fang
RSC Advances 2016 vol. 6(Issue 27) pp:23074-23084
Publication Date(Web):23 Feb 2016
DOI:10.1039/C5RA26176G
In this report, we present a facile method for the synthesis of porous MnCo2O4 nanorods. When the as-synthesized MnCo2O4 nanorods are applied as the anode material for lithium-ion batteries, they exhibit excellent electrochemical performance owing to their porous nature. Because of the delicate balance between structural stability and specific surface area, the porous MnCo2O4 nanorods show high discharge capacity and excellent cycling stability. The initial discharge capacity is 1845 mA h g−1 at a current density of 0.4 A g−1. Even being cycled at a current density of 30 A g−1, the discharge capacity is still about 533 mA h g−1. The effects of binders on the electrochemical performance of the electrode have also been investigated, showing that the CMC/SBR binder is more suitable than PVDF for the as-synthesized porous MnCo2O4 nanorods. The influences of the calcination temperature also have been systematically investigated, which suggest the electrochemical performance is determined by both the structural stability and surface area of the samples.
Co-reporter:Zhen Fang, Tingting Qiang, Jiaxin Fang, Yixuan Song, Qiuyang Ma, Ming Ye, Feiqiang Qiang, Baoyou Geng
Electrochimica Acta 2015 Volume 151() pp:453-458
Publication Date(Web):1 January 2015
DOI:10.1016/j.electacta.2014.11.063
Co-reporter:Tingting Qiang, Jiaxin Fang, Yixuan Song, Qiuyang Ma, Ming Ye, Zhen Fang and Baoyou Geng
RSC Advances 2015 vol. 5(Issue 22) pp:17070-17075
Publication Date(Web):02 Feb 2015
DOI:10.1039/C4RA16242K
Ge@C core–shell nanostructures were successfully synthesized by a facile n-hexane pyrogenation-reducing process. The Ge@C core–shell nanostructures exhibit excellent cycling performance and rate capability in comparison with pure Ge nanoparticles when used as an anode material for a lithium ion battery. The thin carbon shell endows the obtained Ge@C nanostructures with a high specific capacity of 985 mA h g−1 at a current density of 500 mA g−1 after 50 cycles. Furthermore, a discharge capacity of 850 mA h g−1 was observed at a current density of 4000 mA g−1. The excellent lithium storage performance can be attributed to the unique carbon shell structure. The carbon shell not only acts as the buffer layer to maintain structural stability during lithiation, but also increases electrical conductivity during the charge/discharge processes. The high rate capacity of the Ge@C nanostructures demonstrates it a promising anode material for high power lithium-ion batteries.
Co-reporter:Liuyang Long, Hui Zhang, Ming Ye and Zhen Fang
RSC Advances 2015 vol. 5(Issue 16) pp:12224-12229
Publication Date(Web):06 Jan 2015
DOI:10.1039/C4RA14476G
Hollow TiO2 nanospheres are promising anode materials for lithium ion batteries. The synthesis of such nanostructures was achieved by an ammonia cation-assisted oxygen bubble template strategy in the present work. The formation of other transition metal-based hollow spheres also validates the proposed ammonia cation-assisted oxygen bubble template method. The formation mechanism was proposed on the basis of an investigation of the time dependency as well as the effect of H2O2 and NH4Cl on the morphology. The discharge capacity of the prepared hollow TiO2 nanospheres is 131 mA h g−1 after 30 cycles.
Co-reporter:Zhen Fang, Liuyang Long, Shenghua Hao, Yixuan Song, Tingting Qiang and Baoyou Geng
CrystEngComm 2014 vol. 16(Issue 10) pp:2061-2069
Publication Date(Web):09 Dec 2013
DOI:10.1039/C3CE41970C
Anatase TiO2 nanobricks of hierarchical hollow structure with ordered arranged nanothorns are obtained by post-treating the mesocrystal NH4TiOF3 nanobricks with H3BO3 solution. The mesocrystal NH4TiOF3 is formed by an oriented self-assembly process. The similarities in crystal structures between NH4TiOF3 and TiO2 may offer the possibility for the formation such an ordered hollow structure with nanothorns. The obtained hollow TiO2 nanobricks exhibit enhanced photocatalytic activity in degrading organic contaminants compared with other samples.
Co-reporter:Zhen Fang, Shenghua Hao, Liuyang Long, Hui Fang, Tingting Qiang and Yixuan Song
CrystEngComm 2014 vol. 16(Issue 12) pp:2404-2410
Publication Date(Web):24 Dec 2013
DOI:10.1039/C3CE42082E
Single-crystal SnSe2 nanosheets with a ten atomic-layer thickness have been prepared by a facile solvothermal route reaction in benzyl alcohol in the presence of PVP. Benzyl alcohol acts as the solvent and reducing reagent to promote the formation of the hexagonal phase of SnSe2, and the presence of PVP provides a stable environment for the construction of the SnSe2 nanosheets. A reasonable formation mechanism was put forward on the basis of the time-dependent experiments. The obtained SnSe2 nanosheets displayed an enhanced photocurrent compared to the thick SnSe2 nanoplates, which indicated potential applications in photodetectors, photovoltaic devices and so forth.
Co-reporter:Chenyan Wang, Zhen Fang, Fan Fan, Xiaona Dong, Yin Peng, Shenghua Hao and Liuyang Long
CrystEngComm 2013 vol. 15(Issue 29) pp:5792-5798
Publication Date(Web):15 May 2013
DOI:10.1039/C3CE00037K
A simple strategy to synthesize monodispersed and highly-homogeneous Cu39S28 micro/nano-crystals via a solvothermal method was reported. The structure, morphology and size of the products were characterized by X-ray powder diffraction, X-ray energy dispersive spectroscopy, scanning electron microscopy and transmission electron microscopy. It was found that the size of the products could be tuned by the dosage of PVP, reaction temperature and concentration of reactants. A reasonable nucleation–Ostwald ripening–anisotropy growth mechanism was proposed for the formation of the Cu39S28 hierarchical sphere-like structure based on the time-dependent electron microscopy observations. The visible-light photocatalytic activity of different sizes was evaluated by the degradation of Rhodamine B in the presence of H2O2. For their efficient hydroxyl radicals yielding, the small-sized NCs have a superior photocatalytic activity. Universal visible-light photocatalytic activity of the obtained nanocrystals was also demonstrated. Our results may open up an efficient way for treatment of the dye contaminated waste water using solar radiation.
Co-reporter:Zhen Fang;Chenyan Wang;Fan Fan;Shenghua Hao;Liuyang Long;Yixuan Song ;Tingting Qiang
Chinese Journal of Chemistry 2013 Volume 31( Issue 8) pp:1015-1021
Publication Date(Web):
DOI:10.1002/cjoc.201300200
Abstract
The transformation mechanisms of thiourea in ethylene glycol solution was systematically investigated in this report, which shows the transformation process is influenced by the anion (NO3−, Cl−, Br−) and polyvinylpyrrolidone (PVP). Thiourea (tu) isomerizes into ammonium thiocyanate when NO3− is present, regardless of the existence of PVP. For Cl−, thiourea coordinates with copper anion to form [Cu(tu)]Cl·1/2H2O complex whether PVP is present. When it comes to Br−, thiourea hydrolyzes in the cooperation of PVP or coordinates with copper anion to form [Cu(tu)Br]·1/2H2O complex without PVP. The different transformation routes will lead to different phase evolution of the CuS system. This work may provide a new understanding of the transformation of thiourea in ethylene glycol solution. The optical properties of the as-prepared copper sulfides exhibit signi?cant stoichiometry-dependent features which may have potential applications in semiconductor photovoltaic devices.
Co-reporter:Zhen Fang, Qin Wang, Xiaoqing Wang, Fan Fan, Chenyan Wang, Xiaojun Zhang
Materials Research Bulletin 2013 48(11) pp: 4935-4941
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.07.023
Co-reporter:Zhen Fang, Fan Fan, Zekun Ding, Chenyan Wang, Liuyang Long, Shenghua Hao
Materials Research Bulletin 2013 48(4) pp: 1737-1740
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.01.005
Co-reporter:Zhen Fang;Qin Wang;Xiaoqing Wang;Baichuan Zhu;Fan Fan;Chenyan Wang;Xiaowang Liu
Crystal Research and Technology 2012 Volume 47( Issue 6) pp:635-642
Publication Date(Web):
DOI:10.1002/crat.201200112
Abstract
A simple ethylenediamine-assisted hydrothermal method was developed for the synthesis of sheet-like PbS nanostructures. Studies show that ethylenediamine not only provides a weakly basic environment for the reaction system, but also acts as a capping reagent to control the growth habit of cubic PbS. A reasonable growth mechanism for the PbS nanosheet structure has been proposed on the basis of the experimental studies. The structure, morphology, and composition of the nanosheets have been characterized by X-ray powder diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy.
Co-reporter:Zhen Fang, Yufeng Liu, Xiaowang Liu, Qin Wang, Yueting Fan and Weizhi Wang
CrystEngComm 2011 vol. 13(Issue 19) pp:5653-5657
Publication Date(Web):22 Jul 2011
DOI:10.1039/C1CE05588G
We demonstrated a new strategy for the preparation of the cubic phase Cu1.8S rattle-type structure via a dynamic isomers engaged solution route. The isomerization of thiourea into ammonium thiocyanate under solvothermal condition results in the formation of Cu1.8S and CuSCN in initial products. The transformation of CuSCN into Cu1.8S causes detachment between the core and shell. Studies show that the homogeneity and size of the rattle-type structure can be controlled by varying the concentration of precursor and PVP. These novel Cu1.8S rattle-type structures exhibit photoconductivity and may have potential applications in semiconductor optoelectronic devices.
Co-reporter:Zhen Fang;Yueting Fan;Yufeng Liu
Frontiers of Optoelectronics 2011 Volume 4( Issue 1) pp:
Publication Date(Web):2011 March
DOI:10.1007/s12200-011-0165-6
In this paper, a photochemical synthesis of ZnS-amorphous carbon nanotubes (ACNTs/ZnS) composites using ACNTs was reported, whose surface were modified with carboxylic groups as a support. The size and distribution of ZnS nanoparticles can be controlled by adjusting the initial amount of reactants and the reaction time. The ACNTs/ZnS nanocomposites were characterized by X-ray power diffraction, scanning electron microscopy and transmission electron microscopy. Studies showed that ACNTs/ZnS nanocomposites had high photocatalytic activity toward the photodegradation of dye molecule.
Co-reporter:Zhen Fang ; Yufeng Liu ; Yueting Fan ; Yonghong Ni ; Xianwen Wei ; Kaibin Tang ; Jianmin Shen ;Yuan Chen
The Journal of Physical Chemistry C 2011 Volume 115(Issue 29) pp:13968-13976
Publication Date(Web):June 21, 2011
DOI:10.1021/jp112259p
Bi2S3 nanowire/CdS nanoparticle heterostructure has been designed and constructed through an easy wet-chemistry approach at 140 °C for 8 h. The product is mainly composed of Bi2S3 nanowires, several hundred nanometers long and 10 nm wide, and epitaxially grown triangle-like CdS nanoparticles with size of 20 nm at their surfaces. A possible sequential deposition growth mechanism is proposed on the basis of experimental results to reveal the formation of the nanoscale heterostructure. Under the irradiation of UV light, the as-prepared nanoscale Bi2S3/CdS heterostructure exhibits enhanced photochemical efficiency that can be mainly attributed to the microstructure of the product. In the nanoscale heterostructure, the CdS nanoparticle not only determines the overall band gap energy, but also controls the charge carrier transition, recombination, and separation, while the Bi2S3 nanowire serves as support for the CdS nanoparticle, defines the specific surface area of the product and thus influences the photocatalytic activity. The effects of reaction parameters on the structure and photocatalytic activity of the final product are also discussed.
Co-reporter:Zhen Fang, Xueying Wang, Jianmin Shen, Xiu Lin, Yonghong Ni and Xianwen Wei
Crystal Growth & Design 2010 Volume 10(Issue 2) pp:469-474
Publication Date(Web):December 31, 2009
DOI:10.1021/cg9006263
Double fold hexagonal dendrites (DFHD) of copper(I) sulfide with D6h point group symmetry were synthesized by an ammonia-assisted hydrothermal process. The growth direction of the branches in DFHD could be tuned by adjusting the concentration of reagents, such as Cu2+ and NH3. Studies show that the coordination effect between copper anion and ammonia ligands plays a crucial role in the formation of the final dendritic structure. The influences of the reaction temperature and time on the morphology of the product have been also discussed. A possible formation process of this novel DFHD has been proposed on the basis of experiments.
Co-reporter:Dr. Zhen Fang;Xiu Lin;Xia Jian;Xueying Wang;Xianwen Wei;Feng Tao
Chinese Journal of Chemistry 2010 Volume 28( Issue 12) pp:2377-2382
Publication Date(Web):
DOI:10.1002/cjoc.201190007
Abstract
The copper oxide (CuO) hierarchical nanostructures were synthesized by a simple hydrothermal reaction, using copper(II) acetylacetonate and NaOH as the reactants. The morphologies of CuO nanostructures are strongly influenced by the dosage of copper(II) acetylacetonate, alkali concentration and reaction temperature. The possible formation process was also discussed on the basis of time-dependent experiments. This simple solution-phase method may be useful for morphological synthesis of other oxides nanocrystals.
