Gradient particle size and loading mitigate platinum degradation and performance decay of proton exchange membrane fuel cell

The platinum catalysts in proton exchange membrane (PEM) fuel cell are costly and prone to degradation, which considerably affects the cost and durability of fuel cell. Under dynamic loading or idling conditions, the platinum catalysts near the PEM side degrade severely, which is the main reason for performance decay of fuel cell. A one-dimensional platinum degradation model was established to simulate the degradation process of platinum catalysts with gradient particle size and loading design. Subsequently, the characteristic parameters of degraded platinum were coupled with a three-dimensional fuel cell model to explore the effect of platinum degradation on fuel cell performance decay. The results show that the design strategy of gradient particle size (larger particle near PEM) can significantly mitigate the platinum degradation and performance decay, at the cost of minor decline of initial performance of fuel cell. In contrast, the design strategy of gradient platinum loading (higher platinum loading near PEM) overall promotes the platinum degradation but has little effect on fuel cell performance decay. Finally, the particle size gradient was optimized to minimize platinum degradation and performance decay and maintain the initial performance as much as possible. This study can provide a reference for the design of highly durable platinum catalysts.