The effects of two catalyst fabrication techniques, impregnation method and colloidalmethod, on the performance of the oxygen electrode are studied and the difference in the catalyticactivity of the two kinds of catal...The effects of two catalyst fabrication techniques, impregnation method and colloidalmethod, on the performance of the oxygen electrode are studied and the difference in the catalyticactivity of the two kinds of catalysts towards oxygen reduction are also analyzed with the aid ofTEM and XRD. Based on the results and analysis, the following conclusions are obtained :thecatalyst fabricatin technique exerts an effect on the performance of the oxygen electrode, com-paring the performance of the Pt/C catalyst prepared by impregnation method with that of thePt/C catalyst prepared by colloidal method, the latter shows a higher catalytic activity towardsoxygen reduction; Pt/C electrocatalyst has small particle size and large fraction of Pt(111) crystalsurface.展开更多
At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components o...At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components of PEMFC-membrane-electrode assembly (MEA) and seek feasible measures to avoid degradation. The effect of freeze/thaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freeze/thaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable performance under subzero temperature and gas purging is proved to be the effective operation.展开更多
文摘The effects of two catalyst fabrication techniques, impregnation method and colloidalmethod, on the performance of the oxygen electrode are studied and the difference in the catalyticactivity of the two kinds of catalysts towards oxygen reduction are also analyzed with the aid ofTEM and XRD. Based on the results and analysis, the following conclusions are obtained :thecatalyst fabricatin technique exerts an effect on the performance of the oxygen electrode, com-paring the performance of the Pt/C catalyst prepared by impregnation method with that of thePt/C catalyst prepared by colloidal method, the latter shows a higher catalytic activity towardsoxygen reduction; Pt/C electrocatalyst has small particle size and large fraction of Pt(111) crystalsurface.
基金Supported by the National Natural Science Foundation of China (No.20206030) and Ministry of Science and Technology 863 Hi-Technology Research and Development Program of China (2005AA501660).
文摘At subzero temperature, the startup capability and performance of polymer electrolyte membrane fuel cell (PEMFC) deteriorates markedly. The object of this work is to study the degradation mechanism of key components of PEMFC-membrane-electrode assembly (MEA) and seek feasible measures to avoid degradation. The effect of freeze/thaw cycles on the structure of MEA is investigated based on porosity and SEM measurement. The performance of a single cell was also tested before and after repetitious freeze/thaw cycles. The experimental results indicated that the performance of a PEMFC decreased along with the total operating time as well as the pore size distribution shifting and micro configuration changing. However, when the redundant water had been removed by gas purging, the performance of the PEMFC stack was almost resumed when it experienced again the same subzero temperature test. These results show that it is necessary to remove the water in PEMFCs to maintain stable performance under subzero temperature and gas purging is proved to be the effective operation.
