Activating inert bismuth atoms via interfacial p-d orbital hybridization: a robust strategy for efficient oxygen evolution reaction.

Unlocking the catalytic potential of inert atoms via precise electronic structure modulation serves as an effective approach to surmount the kinetic limitations of the oxygen evolution reaction (OER), yet it remains technically challenging. In this study, a Bi/NiS heterojunction electrocatalyst was successfully synthesized, and the activation of inert Bi atoms was realized via interfacial p-d orbital hybridization for alkaline OER. Experimental characterizations and density functional theory (DFT) calculations reveal that the strong p-d hybridization between Bi 6p and Ni 3d orbitals induces profound electronic structure reconstruction of Bi sites, which not only builds a high-efficiency electron transfer channel near the Fermi level, but also precisely modulates the bonding behavior between Bi sites and OER intermediates, as well as the BiBi interatomic bonding. Benefiting from this modulation, the inert Bi sites are successfully activated to serve as the primary OER active centers, endowing the Bi/NiS catalyst with ultralow overpotential (η10 = 179 mV), fast reaction kinetics (Tafel slope = 37.1 mV dec-1), and exceptional long-term operational stability (150 h), outperforming pure Bi and commercial RuO2. This study presents a viable strategy for activating inert p-block metals and offers important implications for the design of high performance OER electrocatalysts.