-
[show abstract]
[hide abstract]
ABSTRACT: Porous Pt nanostructure decorated sulfur microparticles (Pt@S) are fabricated using sulfur as the template. The Pt@S electrode shows a higher volumetric specific capacity of 520 mA h cm(-3) and improved cyclability with only 15% capacity fading after 80 cycles at 0.1 C (167.5 mA g(-1)).
Chemical Communications 04/2013; · 6.17 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, one-dimensional (1D) mesoporous single-crystalline Co(3)O(4) nanobelts are synthesized by a facile hydrothermal method followed by calcination treatment. The as-prepared nanobelts have unique mesoporous structures, which are constructed by many interconnected nanocrystals with sizes of about 20-30 nm. And typical size of the nanobelts is in the range of 100-300 nm in width and up to several micrometers in length. The BET surface area of Co(3)O(4) nanobelts is determined to be about 36.5 m(2) g(-1) with dominant pore diameter of 29.2 nm. Because of the 1D structure, mesoporous morphologies and scrupulous nanoarchitectures, the Co(3)O(4) nanobelts show excellent electrochemical performances such as high storage capacity and superior rate capability. The specific capacity of Co(3)O(4) nanobelts could remains over 614 mA h g(-1) at a current density of 1 A g(-1) after 60 cycles. Even at a high current density of 3 A g(-1), these Co(3)O(4) nanobelts still could deliver a remarkable discharge capacity of 605 mA h g(-1) with good cycling stability.
ACS Applied Materials & Interfaces 10/2012; · 4.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Bismuth tungstate (Bi(2)WO(6)) has attracted great research interest as an important visible-light-responsive photocatalyst. In this paper, we report a facile hydrothermal route for the shape-controlled synthesis of micro/nanostructured Bi(2)WO(6), without adding surfactants or templates. The results show that various morphologies of Bi(2)WO(6) including coralloid spherical particles, packed nanosheets, fluffy microspheres, and plates can be obtained by adjusting the pH values of the precursors. The as-prepared porous fluffy microspheres with a hierarchical architecture synthesized at pH 8 exhibit the highest photocatalytic activity for the degradation of Rhodamine (RhB) under visible light irradiation. The photodegradation efficiency reaches as high as 99% within 20 min irradiation. This enhanced photocatalytic activity can be attributed to the unique porous structure and high BET surface area of fluffy microspheres with hierarchical architecture.
Journal of Colloid and Interface Science 03/2012; 370(1):132-8. · 3.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A novel ZnO/ZnO-Bi2O3 nanocomposite was prepared by a homogeneous precipitation method. The nucleation sites, namely ZnO-Bi2O3 particles with nominal chemical composition of (ZnO)0.94(Bi2O3)0.06, were prepared by ball milling and subsequent annealing treatment. The as-synthesized materials were characterized by XRD, SEM and electrochemical measurements. Compared with single ZnO, the ZnO/ZnO-Bi2O3 nanocomposite show better cycling stability and higher discharge capacity. When the content of ZnO-Bi2O3 was 15 wt.%, the discharge capacity of ZnO/ZnO-Bi2O3 nanocomposite hardly declined over 60 cycling test, the average discharge capacity reached 590.2 mAh g-1. Cyclic voltammograms clearly illuminated that the added ZnO-Bi2O3 particles could decrease electrode polarization, maintain the electrochemical activity, and enhance the discharge capacity of ZnO.
2011 International Conference on Chemical, Material and Metallurgical Engineering, ICCMME 2011, December 23, 2011 - December 25, 20112011 International Conference on Chemical, Material and Metallurgical Engineering, ICCMME 2011, December 23, 2011 - December 25, 2011, Beihai, China; 01/2012
-
[show abstract]
[hide abstract]
ABSTRACT: Amorphous porous FePO4·3H2O micro-spheres were synthesized via a controlled crystallization method. These micro-spheres have a particle size distribution from 10 to 28 m. There are larger numbers of pores on the surface of FePO4·3H2O microspheres, which are important to synthesize high performance LiFePO4 cathode materials for the application of lithium ion battery. The electrochemical properties of the LiFePO4/C electrode, preparing by using the above porous spherical FePO4·3H2O particles, were measured. The electrochemical results show that the obtained LiFePO 4/C has a high initial discharge specific capacity of 141.4 mAhg -1 and good cycling performance at 0.5 C. The microstructural and electrochemical analyses indicate that this porous spherical FePO 4·3H2O is a fascinating precursor for preparing LiFePO4/C cathode materials.
2011 International Conference on Chemical, Material and Metallurgical Engineering, ICCMME 2011, December 23, 2011 - December 25, 20112011 International Conference on Chemical, Material and Metallurgical Engineering, ICCMME 2011, December 23, 2011 - December 25, 2011, Beihai, China; 01/2012
-
[show abstract]
[hide abstract]
ABSTRACT: A new kind of cathode materials, Li3V2(PO 4)3/C nanocomposites, has been prepared via one-step solid-state reaction using ultra low-cost asphalt as both reduction agents and carbon sources. The asphalt is contained 60.37% of fixed carbon and 0.18% of other impurity.It is purchased from Zhen jiang Xin Guang Metallurgical Subsidiary Material Plant. Structural analysis shows that the obtained Li 3V2(PO4)3/C nanocomposites contain abundant Li3V2(PO4)3 nanorods and micro/nano particles encapsulate with carbon shells. The Li3V 2(PO4)3/C nanocomposites achieve enhanced dischargeability, reversibility, and cycleability. Electrochemical tests show that the Li3V2(PO4)3/C nanocomposite has initial discharge capacities of 170 mAhg-1 at 0.1C in the voltage range of 3.0 to 4.8 V. The improved electrochemical properties of the Li 3V2(PO4)3/C nanocomposites are attributed to the presence of Li3V2(PO4) 3/C nanorods and the electronically conductive carbon shell. This one-step solid state reaction using low-cost asphalt as carbon sources is feasible for the preparation of the Li3V2(PO 4)3/C nanocomposites which can offer favorable properties for commercial applications.
2011 International Conference on Chemical, Material and Metallurgical Engineering, ICCMME 2011, December 23, 2011 - December 25, 20112011 International Conference on Chemical, Material and Metallurgical Engineering, ICCMME 2011, December 23, 2011 - December 25, 2011, Beihai, China; 01/2012
-
[show abstract]
[hide abstract]
ABSTRACT: TiO2-xNxfilm was prepared by the combination of sol-gel and spin-coating method on indium-tin oxide (ITO) conducting glass substrate. Then an ITO/TiO2-xNx/NiO composite electrode was obtained by chemical bath deposition (CBD). The morphology, crystal structure and composition of the ITO/TiO2-xNx film were characterized by SEM, XRD, and XPS. The photoelectrochemical properties of the ITO/TiO2-xNx/NiO electrode were evaluated by photocurrent transient measurements and UV-visible transmittance spectra. The results showed that the ITO/TiO2-xNx/NiO electrode was sensitive to light and exhibited a noticeable photoelectrochromism. (2011) Trans Tech Publications, Switzerland.
1st International Congress on Advanced Materials 2011, AM2011, May 13, 2011 - May 16, 20111st International Congress on Advanced Materials 2011, AM2011, May 13, 2011 - May 16, 2011, Jinan, China; 01/2011
-
[show abstract]
[hide abstract]
ABSTRACT: Hexagonal phase NaYF4: Eu3+materials were successfully synthesized by a facile EDTA-assisted hydrothermal route. The microstructure, morphology and luminescence property of the as-synthesized samples were characterized by XRD, XPS, SEM, TEM, HRTEM and photoluminescence (PL) spectra. The pristine NaYF4: Eu3+microprisms have uniform size and morphology with 3-4 micrometers in length and ca. 500 nm in diameter. The annealing treatment afterwards achieved high crystallinity, and moreover, had a remarkable influence on morphologies of the NaYF4: Eu3+sample. In comparison with the pristine sample, the annealed NaYF4: Eu3+microcrystals had a markedly enhancement of down-conversion (DC) luminescence properties, which may be due to the high crystallinity and large surface roughness resulted from annealing treatment. (2011) Trans Tech Publications.
2011 International Conference on Materials and Products Manufacturing Technology, ICMPMT 2011, October 28, 2011 - October 30, 20112011 International Conference on Materials and Products Manufacturing Technology, ICMPMT 2011, October 28, 2011 - October 30, 2011, Chengdu, China; 01/2011
-
[show abstract]
[hide abstract]
ABSTRACT: Unique amorphous FePO4 with particle size ranging from 20 to 80 nm has been successfully synthesized by a new cost-effective electrochemical method. This FePO4 possesses a mesoporous structure with specific surface area of 65.2 m2 g-1 and dominant pore diameter of 23.6 nm. The basic formation mechanism has been discussed. These amorphous mesoporous FePO4 nanoparticles can be used as precursors to prepare LiFePO4/C nanocrystals with porous structure. The obtained LiFePO4/C cathode materials exhibit excellent cycling performances. At a 0.5 C rate, the discharge capability is above 140.0 mA h g-1 and the capacity retention rate is higher than 98% after 50 cycles. The microstructural and electrochemical analyses reveal that these amorphous mesoporous FePO4 nanoparticles are the perfect precursors to prepare LiFePO4/C composite. Furthermore, this facile, cost-effective and green electrochemical strategy can be easily scaled up for commercialization, and also could open avenues towards synthesizing other mesoporous phosphate materials. 2011 Elsevier Inc. All rights reserved.
Microporous and Mesoporous Materials 01/2011; · 3.29 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A sliding probe technique has been developed for the in situ electrical property characterization of individual nanostructures inside a transmission electron microscope (TEM) using a nanomanipulator. Experimental investigation into the transport measurement of copper-filled carbon nanotubes, carbide nanowires, and carbon microfiber has shown the effectiveness of this method. Comparing with conventional 4-point methods, the proposed setup is simple and agile and it can be readily combined with TEM-based imaging and analysis. Comparing with conventional 2-point methods, the sliding probe method are characterized by (1) the contact resistance can be partially eliminated and (2) sectional measurement using this method is particularly adaptable to non-uniform structures or hetero-structures.
Nanotechnology Materials and Devices Conference (NMDC), 2010 IEEE; 11/2010
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, we report the use of binary carbon supports (carbon nanotubes (CNTs) and active carbon) as a catalyst layer for fabricating gas diffusion electrodes. The electrocatalytic properties for the oxygen reduction reaction (ORR) were evaluated by polarization curves and electrochemical impedance spectroscopy (EIS) in an alkaline electrolyte. The binary-support electrode exhibits better performance than the single-support electrode, and the best performance is obtained when the mass ratio of carbon nanotubes and active carbon is 50:50. The results from the electrode kinetic parameters indicate that the introduction of carbon nanotubes as a secondary support provides high accessible surface area, good electronic conductivity, and fast ORR kinetics. Furthermore, the effect of CNT support on the electrocatalytic properties of Pt nanoparticles for binary-support electrodes was also investigated by different loading-reduction methods. The electrocatalytic activity of the binary-support electrodes is improved dramatically by Pt loading on CNT carbon support, even at very low Pt loading. Additionally, the EIS analysis results indicate that the process of ORR may be controlled by diffusion of oxygen in the electrode thin film for binary-support electrodes with or without Pt catalyst.
Journal of Colloid and Interface Science 05/2005; 284(2):593-9. · 3.07 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: LiFePO4/C composite cathode materials with carbon nano-interconnect structures were synthesized by one-step solid state reaction using low-cost asphalt as both carbon source and reducing agent. Based on the thermogravimetry, differential scanning calorimetry, transmission electron microscopy and high-resolution transmission electron microscopy, a growth model was proposed to illustrate the formation of the carbon nano-interconnect between the LiFePO4 grains. The LiFePO4/C composite shows enhanced discharge capacity (150 mAh g−1) with excellent capacity retention compared with the bare LiFePO4 (41 mAh g−1) due to the electronically conductive nanoscale networking provided by the asphalt-based carbon. The results prove that the asphalt is a perfect carbon source and reduction agent for cost-effective production of high performance LiFePO4/C composite.
Electrochimica Acta. 55(8):2592-2596.
-
[show abstract]
[hide abstract]
ABSTRACT: An industrial electrolytic cell was designed for the electrochemical synthesis of N-methylhydroxyl-amine hydrochloride (N-MHA). Copper was used as the cathode, graphite as the anode, and a cation membrane as the separator. The results show that N-MHA with a high purity of 99% can be electrosynthesized directly from nitromethane in HCl solution. Under a constant current of 1000–2500A·m−2 in the temperature of 30–50°C, the average yield, current efficiency, and reaction selectivity were 65%, 70%, and 99%, respectively. Graphite electrode and membrane material can be used continuously in the preparative electrolysis for 5000h. Moreover, the effects of the electrode and membrane materials, current intensity, electrolyte temperature, and other associated parameters on the electrosynthesis results were investigated. The direct current power consumption was 8151.3kW·h·(1000kg N-MHA)−1. This method is a simple separation process with limited contamination and hence, is a new green synthesis method for the industrial production of N-MHA.
Chinese Journal of Chemical Engineering.
-
[show abstract]
[hide abstract]
ABSTRACT: A high-yield of carbon nanotubes filled with β-Sn nanowires has been produced by the thermal pyrolysis of acetylene over SnO2 catalysts. Electron beam irradiation (EBI) induced melting and flow of Sn in the nanotubes and this could be controlled by changing the electron beam current density. The mass flow rate of the Sn ranged from 0.9 to 8.2 fg/s. The melting of the nanowires is a result of the temperature rise caused by the EBI. Many factors, including temperature variation, charging, and EBI induced deformation of the carbon shells, contribute to the flow of Sn.
Carbon.
