Interfacial Interaction Engineering of FeCoS@CoMoP for pH-Universal H<sub>2</sub> and Alkaline Medium O<sub>2</sub> Evolution

Abstract

Engineering efficient catalyst interfaces offers a constructive way to boost activity and stability in the field of water electrolysis. Here, unique core-shell FeCoS@CoMoP heterostructure nanoparticles are rationally fabricated on a porous Ni foam through hydrothermal and electrodeposition methods. The as-prepared electrocatalyst exhibits efficient pH-universal hydrogen evolution reaction (HER) activity along with a satisfactory alkaline oxygen evolution reaction (OER) performance, extremely small overpotentials, and Tafel values, achieving prominent durability and stability. A series of structural characterizations help identify the reactive centers during the catalytic procedure and the tight interfacial interaction between the shell and core materials. Density functional theory (DFT) calculations reveal that the surface electrodeposition of CoMoP not only tunes the d-band center but also obviously decreases the Gibbs free energies in the HER/OER processes. It can be expected that the three-dimensional self-supported catalytic system will hold strong promise for effective water splitting, energy storage, and energy transformation devices.