Built-in electric field-driven electron transfer behavior at Ru-RuP2 heterointerface fosters efficient and CO-resilient alkaline hydrogen oxidation

Exploiting a cost-effective electrocatalyst for hydrogen oxidation reaction (HOR) with high-performance and CO poisoning resistance is essential for the widespread application of alkaline anion exchange membrane fuel cells (AEMFCs). Herein, we craft a unique Ru-RuP 2 heterostructure within hollow mesoporous carbon sphere (Ru-RuP 2 @C) using phosphide-controlled phase-transition approach. Benefiting from the interfacial electron transfer from RuP 2 to Ru, the Ru-RuP 2 @C electrocatalyst exhibits impressive HOR performance with a mass activity of 2.87 mA μ g Ru − 1 . Notably, Ru-RuP 2 @C demonstrates strong tolerance to 1000 ppm CO, a capability lacking in PtRu/C and Pt/C. When serves as an anode catalyst for AEMFC, it achieves a peak power density of 521 mW cm −2 , comparable to Pt/C. Experimental and theoretical analyses reveal that the built-in electric field, resulting from work function differences, creates an asymmetric charge distribution that modulates the d -band center of Ru-RuP 2 @C. This optimizes the adsorption strength of hydrogen and hydroxide intermediates, thereby accelerating HOR catalytic kinetics.