Tailoring single mesoporous carbon catalyst particles via pore-scale simulation for superior PEM fuel cell performance

Minimizing Pt loading while maintaining high performance is vital for commercializing proton exchange membrane fuel cells. Mesoporous carbon supports enable internal Pt placement, mitigating ionomer poisoning effect and mass transport limitations. However, this also increases proton transport resistance due to limited ionomer accessibility. This work presents a pore-scale model to simulate reactive transport in single catalyst particles. We evaluate the impacts of open pores, pore number, and Pt distribution on oxygen accessibility and performance. Results show that internal Pt outperforms ionomer-coated Pt when sufficient open pores promote mass transport, though performance drops if Pt is located too deeply. To address this issue, we propose a hollow-shell mesoporous carbon design that confines Pt near the outer surface. This approach enhances internal Pt utilization by up to 38% and enables a Pt loading reduction of as much as 50% at equivalent performance. These findings offer a practical strategy for ultra-low Pt catalysts.