Corrosion of carbon support for PEM fuel cells by electrochemical quartz crystal microbalance

摘要

During the voltammetry of carbon supports for proton exchange membrane fuel cells (PEMFCs), includ-ing commercial carbon blacks, graphitized carbon black and multi-wall carbon nanotubes (MWNTs), in deaerated 0.5 M H_2SO_4 solution results in mass changes as observed by using in situ electrochemical quartz crystal microbalance (EQCM). The mass change and corrosion onset potential during electrochem-ical carbon corrosion indicate that oxides are formed and accumulated on the carbon surface, leading to an increase in mass. A decrease in the mass is associated with carbon loss from the gasification of car-bon surface oxides into carbon dioxide. High BET surface area carbon blacks ECP600 and ECP 300 have a carbon loss of 0.0245 ng cm~(-2) s~(-1) and 0.0144 ng cm~(-2) s~(-1) and as compared to 0.0115 ng cm~(-2) s~(-1) for low surface area support XC-72 and so they are less resistant to corrosion. Craphitized XC-72 and MWNTs, with higher graphitization have higher carbon corrosion onset potential at 1.65 V and 1.62 V and appear to be more intrinsically resistant to corrosion.