Enhanced activity and durability of Pt/CeO₂/carbon catalysts for oxygen reduction reaction via metal oxide-mediated carbon etching

The development of advanced catalyst supports is crucial for enhancing the performance and durability of platinum based electrocatalysts in proton exchange membrane fuel cells (PEMFCs). In this study, CeO₂/carbon composites with controlled cerium oxide loadings were synthesized via a facile wet impregnation method, and their potential as electrocatalyst supports was systematically investigated. The incorporation of CeO₂ induced a metal oxide-mediated carbon etching effect during thermal treatment, resulting in enlarged pore structures within the carbon matrix. Platinum nanoparticles (Pt NPs) deposited on these modified supports exhibited similar particle sizes regardless of Ce content, enabling a direct evaluation of support effects on catalytic performance. X-ray absorption spectroscopy revealed that CeO₂ incorporation effectively suppressed surface oxidation of Pt NPs through electronic metal-support interactions. The Ce-incorporated Pt catalysts demonstrated significantly enhanced oxygen reduction reaction (ORR) activity compared to commercial Pt/C catalysts, attributed to the preservation of metallic Pt active sites. More importantly, the optimized Ce-modified Pt catalyst exhibited substantially improved electrochemical durability, retaining 56% of its initial mass activity after 10,000 potential cycles, compared to only 33% retention for commercial Pt/C catalysts. This enhanced stability originates from the synergistic effects of Pt confinement within enlarged pores and suppressed Pt oxidation facilitated by the CeO₂ phase.