Carbon mesopore depth engineering boosts the performance of low-platinum fuel cells

Ionomer adsorption-induced Pt poisoning and high local oxygen transport resistance constitute two critical challenges preventing proton exchange membrane fuel cells from achieving low-Pt loadings. Yet, strategies concurrently mitigating both issues remain limited, making it challenging to achieve satisfactory performance in both kinetically controlled low-current-density and mass transport-controlled high-current-density regions. Herein, we show that this limitation can be addressed with a mesoporous carbon support design whose key lies in constructing a small mesopore-dominated structure while rationally controlling pore depth to a medium level. This design creates an ideal local reaction environment for Pt nanoparticles inside the mesopores, one that protects most Pt from ionomer poisoning while achieving efficient oxygen diffusion. Using the developed carbon support, we synthesize an intermetallic PtCo nanocatalyst that delivers competitive membrane electrode assembly performance at low-Pt cathode loading (0.1 mgPt cm−2), with a H2-air rated power density of 1.23 W cm−2 at 0.67 V under heat-rejection-constrained conditions and a H2-O2 mass activity of 1.1 A mgPt−1. The heavy use of platinum catalysts limits the large-scale deployment of proton exchange membrane fuel cells. Here, the authors report a carbon support design with small mesopore-dominated structures and moderate pore depth that improves performance at low platinum loading.