Ultrafine Pt cluster and RuO2 heterojunction anode catalysts designed for ultra-low Pt-loading anion exchange membrane fuel cells

Abstract

Development of high-performance hydrogen oxidation catalysts with ultralow precious metal loading is critical to the development of next-generation anion-exchange membrane fuel cells. Here, a novel Ru-rich Pt–RuO₂ heterojunction catalyst was synthesized via a solvothermal process followed by thermal treatment. The Pt–RuO₂ catalyst has ultrafine Pt clusters and a heterojunction interface between Pt and RuO₂, which facilitates high hydrogen oxidation activity while minimizing adverse adsorption of the phenyl group in the polymer electrolyte. The performance of a membrane electrode assembly employing the Pt–RuO₂/C reached a peak power density of 0.77 W cm⁻² with an anode Pt loading of 25 μg_Pt cm⁻², achieving a specific power of 31 W mg_Pt⁻¹ under H₂/O₂ conditions. The combined analysis of electrode performance and cost indicates that Pt–RuO₂/C is one of the most promising catalysts that is approaching the U.S. DOE 2020 performance and cost targets for transportation applications.