Decoupling Electronic Effects in Oxygen Reduction Catalysts via a Model Nanowire Platform

Abstract

ABSTRACT Understanding the intrinsic role of electronic structure in governing oxygen reduction reaction (ORR) activity on Pt‐based catalysts remains a long‐standing challenge due to the intrinsic coupling of electronic, strain, and ensemble effects in conventional alloy systems. Here, we establish a well‐defined Pt‐based nanowire (NW) model platform that enables the rigorous decoupling of electronic effects from structural contributions. By selectively incorporating electron‐donating Re (PtRe) or electron‐withdrawing Au (PtAu) into Pt NWs while maintaining identical morphology, surface structure, and coordination environment, the electronic contribution to ORR is isolated with minimal interference of strain and ensemble effects. A consistent activity trend (PtRe > Pt > PtAu) is observed from intrinsic ORR activity to device‐level membrane electrode assembly performance. Crucially, a correlation is established between the electronic structure, intermediate adsorption behavior, and intrinsic activity. Meanwhile, the high‐activity PtRe NW catalyst also delivers a robust durability with mass activity decline of 11.8% and voltage loss of 12 mV after 30,000‐cycle tests. In situ spectroscopy and theoretical calculations results collectively confirm that Re dopants donate electrons to Pt, generating an electron‐rich Pt surface that lowers the adsorption energy of oxygen intermediates and enhances ORR activity, while the Au dopant generates an opposite effect.