Unlocking Synergistic Catalysis in NiP: Dual Role of Electronic Structure and Lewis Acidity for Enhanced Oxygen Evolution Reaction

Nickel phosphides (NixPy) are recognized as promising alternatives to noble-metal catalysts for the oxygen evolution reaction (OER). NiP, consisting of the equal stoichiometric ratio of Ni and P, could help quantify the catalytic effect of P and Ni. In this work, density functional theory (DFT) is employed to investigate the OER mechanism on NiP surfaces. We found that P atoms help stabilize O* at the adsorption sites. The rich electron donation from the Ni atom can alter the local charge distribution and enhance the interaction between O* and P atoms. Both oxygen intermediate adsorption energy and OER overpotential exhibit linear correlations with the charge of adsorption sites. Electron loss at the site induces the overall system to exhibit Lewis acidic characteristics, facilitating the OER and leading to a substantial overpotential reduction of up to 0.61 V compared to Lewis basic structures. Leveraging electronic structure theory and Lewis acid–base theory, we offer a new insight into the OER mechanism on the NiP surface, demonstrating that the catalytic activity of bulk metallic surface materials like NiP can be optimized by tailoring the local surface chemical environment.