Degradation Mechanism and Mitigation Strategy of Mesoporous Carbon-Supported Pt Catalysts during Realistic Startup and Air Confinement Shutdown in Polymer Electrolyte Fuel Cells

Achieving both high performance and durability is critical for polymer electrolyte fuel cells (PEMFCs). Mesoporous carbon (MPC) catalysts have attracted significant attention as promising materials for high-efficiency systems due to their high activity. In this study, we evaluated the durability of MPC catalysts under realistic startup/shutdown (SU/SD) conditions involving power generation and air confinement. Comprehensive analyses, including time-resolved monitoring of CO2 evolution and Pt dissolution, revealed that the MPC catalyst is susceptible to severe performance degradation. We found that MPC undergoes carbon corrosion driven by SU/SD conditions, particularly in regions with limited proton access, resulting not only in mass transport issues but also in severe Pt particle growth. Furthermore, we demonstrated that controlling the upper potential limit via power generation effectively mitigates this degradation by suppressing Pt oxidation and accelerating oxygen consumption, which mitigates the carbon corrosion. This study identifies critical concerns regarding the long-term operation of MPC catalysts and provides a practical strategy for suppressing degradation in real-world environments.