Enabling Efficient Oxygen Reduction Reaction with Pt Single Atoms on Carbide: A Phosphorus-Doped Mo ₂ C Interface Strategy

Developing efficient and cost-effective oxygen reduction reaction (ORR) catalysts is a critical process in electrochemical energy conversion technologies. Here, we report a new heterostructured electrocatalyst composed of phosphorus-doped Mo₂C coupled with atomically dispersed Pt sites (Pt/P-Mo₂C). This is realized through a confined polymerization approach using heteropolyacid-pyrrole complexes and subsequent covalent anchoring. Phosphorus doping plays a crucial role in enhancing the interfacial electron density and enabling strong electronic interactions with Pt atoms. The results showed that the interfacial electronic structure of Pt is significantly modulated, with a downshifted d-band center that optimizes the adsorption/desorption energetics of ORR intermediates. As a result, Pt/P-Mo₂C demonstrates outstanding ORR activity in alkaline media, achieving a half-wave potential (<i>E</i>_1/2) of 0.91 V along with excellent stability. This work presents a generic strategy for integrating single-atom noble metals with carbide supports and highlights the role of interfacial electron engineering in the design of next-generation ORR electrocatalysts.