Electrochemical characteristics and performance of CoTMPP/BP oxygen reduction electrocatalysts for PEM fuel cell

Microwave synthesis method was applied to prepare CoTMPP/BP oxygen reduction electrocatalysts. The influence of the pre-treatment of BP2000 carbon supports by 6 M HNO3 and 30 wt% H2O2 on the activity of electrocatalysts for oxygen reduction was investigated by means of the measurements of their electrochemical characteristics and performances. Levich-Koutecky plot shows that the number of transferred electrons during oxygen reduction on CoTMPP/BP is found to be between 2 and 4. The observed evidence indicated that the production of hydrogen peroxide has occurred during oxygen reduction in two electrons, and further oxidation of hydrogen peroxide involving two other electrons in the higher potential may also occur. The fuel cell performance of single cells with the different CoTMPP/BP electrocatalysts was examined under actual PEM fuel cell conditions. For hydrogen-oxygen fuel cell system, the maximal output power density reached 150 mW/cm(2) at 50 degrees C. Life test was carried out at a constant of the output current density of 200 mA/cm(2) for CoTMPP/BP electrocatalyst, the single cell output voltage maintains at about 0.5 V for more than 900 min, there was no obvious performance degradation under fuel cell conditions. (c) 2006 Elsevier B.V. All rights reserved.