The corrosion of PEM fuel cell catalyst supports and its implications for developing durable catalysts

Studying the corrosion behavior of catalyst support materials is significant for understanding the degradation of polymer electrolyte membrane (PEM) fuel cell performance and developing durable electrocatalysts. The oxidation of Vulcan carbon black (the most widely used catalyst support for PEM fuel cells) was investigated using various electrochemical stressing methods (fixed-potential holding vs. potential-step cycling), among which the potential-step cycling was considered to mimic more closely the real drive-cycle operation of vehicle PEM fuel cells. The oxidation of carbon was accelerated under potential-step conditions as compared with the fixed-potential holding condition. Increasing the potential-step frequency or decreasing the lower potential limit in the potential-step can further accelerate the corrosion of carbon. The accelerated corrosion of carbon black was tentatively attributed to the cycle of consumption/regeneration of some easily oxidized species. These findings are being employed to develop a test protocol for fast-screening durable catalyst support.