A synergistic Pt-Ru-nitrogen-doped-carbon hydrogen oxidation catalyst

Hydroxide exchange membrane fuel cell (HEMFC) is a potentially cost-effective energy conversion technology. However, current state of the art HEMFCs require a high loading of platinum-group-metal (PGM) catalysts, especially for the hydrogen oxidation reaction (HOR). Here we develop a porous nitrogen-doped carbon-supported PtRu HOR catalyst (PtRu/pN-C) that has the highest reported intrinsic and mass activity in alkaline condition. Spectroscopic and microscopic data indicate the presence of Pt single atoms (SAs) in addition to PtRu nanoparticles on pN-C. Mechanistic study suggests Ru modulates the electronic structure of Pt for an optimized hydrogen binding energy, while Pt-SAs on pN-C optimize the interfacial water structure. These synergetic interactions are responsible for the high catalytic activity of this catalyst. An HEMFC with a low loading of this catalyst and a commercial Fe-N-C oxygen reduction reaction (ORR) catalyst achieves the highest reported PGM utilization rate. The current density at 0.65 V of this HEMFC reaches 1.5 A/cm2, exceeding the US DOE 2022 target (1 A/cm2) by 50 %.