Entity

Time filter

Source Type


Wang G.,Wuhan University of Technology | Wang G.,Hubei Provincial Key Laboratory of Fuel Cell | Wang G.,Hubei Engineering University | Huang F.,Guangdong Academy of Agricultural Sciences | And 10 more authors.
Journal Wuhan University of Technology, Materials Science Edition | Year: 2015

Iridium dioxide with different morphologies (nanorod and nanogranular) is successfully prepared by a modified sol-gel and Adams methods. The catalytic activity of both samples for oxygen reduction reaction is investigated in an alkaline solution. The electrochemical results show that the catalytic activity of the nanogranular IrO2 sample is superior to that of the nanorod sample due to its higher onset potential for oxygen reduction reaction and higher electrode current density in low potential region. The results of Koutecky-Levich analysis indicate that the oxygen reduction reaction catalyzed by both samples is a mixture transfer pathway. It is dominated by four electron transfer pathway for both samples in high overpotential area, while it is controlled by two electron transfer process for both samples in low overpotential area. © 2015, Wuhan University of Technology and Springer-Verlag Berlin Heidelberg. Source


Wang G.,Hubei Engineering University | Wang G.,Wuhan University of Technology | Wang G.,Hubei Provincial Key Laboratory of Fuel Cell | Xu T.,Wuhan University of Technology | And 4 more authors.
Science China Chemistry | Year: 2015

The electrocatalytic activity toward oxygen reduction reaction is studied on the perovskite oxide La1-x Sr x MnO3, as prepared under different firing temperatures. X-ray diffraction shows that three different crystal phases featuring tetragonal, cubic, and orthorhombic symmetries form with increasing crystallinities. The electrocatalytic activity is characterized by cyclic voltammetry and linear sweeping voltammetry for the three phases of La1-x Sr x MnO3. We find that the tetragonal phase has the best catalytic activity among the three crystal phases, with the largest onset potential of 0.147 V. The synergistic effect between the volume per unit cell and crystallinity is indicated to account for the good catalytic activity of the tetragonal phase. © 2015 Science China Press and Springer-Verlag Berlin Heidelberg. Source


Xu T.,Wuhan University of Technology | Xu T.,Hubei Provincial Key Laboratory of Fuel Cell | Wang G.,Wuhan University of Technology | Wang G.,Hubei Provincial Key Laboratory of Fuel Cell | And 4 more authors.
Electrochimica Acta | Year: 2014

Nitrogen shows a positive influence on the ORR activity of certain catalysts, such as N-doped carbon and N-doped ZrO2. In this paper, we report a method to dope nitrogen into La2Zr2O7 nanoparticles by the sol-gel process combined with ammonolysis. XPS results indicate that the nitrogen content in La2Zr2O7 is approximately 0.92 at.%. Compared to the ORR activity of La 2Zr2O7, ORR activity of the N-doped La 2Zr2O7 is considerably enhanced. Density functional theory (DFT) calculations indicate that the band gap is reduced in N-doped La2Zr2O7, which may be one of the factors that contribute to the improvement. © 2014 Elsevier Ltd. Source


Yi Y.,Wuhan University of Technology | Yi Y.,Hubei Provincial Key Laboratory of Fuel Cell | Zheng-kai T.,Wuhan University of Technology | Zheng-kai T.,Hubei Provincial Key Laboratory of Fuel Cell | And 4 more authors.
International Journal of Energy Research | Year: 2012

The importance of gravity effect on the performance of proton exchange membrane fuel cell (PEMFC) has recently been recognized. In this paper, the effect of gravity on the performance of PEMFC has been investigated associating with different gas intake modes. The polarization curves of the stack with different positions of reaction gas inlet and outlet at varied gravitational angles are addressed in detail. The results indicate that the output power of PEMFC stack can be greatly enhanced at the optimized gravitational angle. Gas intake modes that were realized by varying the gas inlet and outlet positions strongly affect the stack performance as well. The optimized performance can be reached at the tilted angle of 90° when both air and hydrogen inlets are placed at the upper side of the stack, whereas the worst performance occurs at the tilted angle of 90° when air and hydrogen flow into the channel from the bottom side of the stack. These results have important implications for PEM fuel cell design and operational strategies. In order to improve the performance, fuel cells should be designed and operated at the optimized gravitational angle and gas inlet/outlet position. © 2011 John Wiley & Sons, Ltd. Source


Yu Y.,Wuhan University of Technology | Yu Y.,Hubei Provincial Key Laboratory of Fuel Cell | Wang G.,Wuhan University of Technology | Wang G.,Hubei Provincial Key Laboratory of Fuel Cell | And 6 more authors.
Electrochimica Acta | Year: 2012

In this paper, the effect of shutoff sequences of hydrogen and air on the degradation behaviours of proton exchange membrane fuel cells (PEMFCs) is investigated with two different shutdown procedures. After one of the gases is shut off, the dummy load is applied to consume the residual gas in the flow field. Theoretical analysis and experimental tests indicate that different gas shutoff sequences have great effect on the oxygen permeation rate across the membrane during introducing the dummy load, resulting in producing the H 2/O 2 interface at the anode in the next startup process. Electrochemical techniques, including the measurement of polarization curves, cyclic voltammetry, and cross-sectional scanning electron microscopy (SEM) of membrane electrode assemblies (MEAs) and transmission electron microscopy (TEM) of Pt/C catalyst are employed to evaluate the performance decay of PEMFCs after 1500 startup and shutdown cycles. The results show that the case if air is shut off firstly would significantly alleviate both the performance decay and the decrease in the electrochemically active surface area, resulting in an improvement in the durability of PEMFCs. © 2012 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations