Study on preparation of cobalt-polypyrrole-carbon black supported Pt catalyst and its single cell performance

Cobalt-polypyrrole-carbon black supported Pt catalyst (Pt/Co-PPy-C) was prepared by pulse-microwave assisted chemical reduction and used as a cathode catalyst for oxygen reduction reaction (ORR) in a single cell; the influence of operation temperature and H₂/air stoichiometric ratio on the cell performances was investigated, in comparison with the commercial Pt/C catalyst. The results indicated that the cell performs best at 70 ℃ and with a H₂/Air ratio of 1.2:2.5. During the 150 h durability test at a galvanostatic operation condition of 600 mA/cm², the voltage degradation rate with Pt/Co-PPy-C as the cathode catalyst is 0.119 mV/h, about 26% of that with the commercial Pt/C catalyst. The cathode charge transfer impedances before and after durability test are about 7.176 and 8.767 mohm, respectively, much smaller than those with the Pt/C catalyst. The average particle size of Pt in Pt/Co-PPy-C is increased from 2.46 to 3.18 nm, also smaller than that for the Pt/C catalyst. The Pt/Co-PPy-C catalyst exhibits superior performance in ORR and may have an enormous application potential in fuel cell.