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

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.