Potential-driven instability effect of carbon supports for Pt/C electrocatalysts

Proton exchange membrane fuel cell (PEMFC) technology is a crucial approach of achieving clean and efficient power generation. However, prior to its full commercialization, several pressing issues must be addressed, especially the dissolution/degradation of Pt-based electrocatalysts for the cathode oxygen reduction reaction (ORR). This degradation significantly reduces the electrocatalytic activity of the catalysts. In this work, the impact of solid carbon support (Vulcan XC-72 R) and porous carbon support (Ketjenblack EC-300) on the degradation process of Pt/C electrocatalysts was investigated. By utilizing various triangular-wave voltage cycles in accelerated durability testing (ADT) protocols, the experimental findings suggest that a lower upper potential limit (UPL) in ADT tends to promote Pt diffusion and further aggregation, while a higher UPL exacerbates the electrochemical dissolution of Pt. Furthermore, the results indicate that Ketjenblack is more proficient than Vulcan XC-72 R in facilitating Pt redeposition after dissolution, which helps to minimize the loss of Pt under standardized rotating disk-electrode (RDE) aqueous electrolyte ADT conditions.