Design and construction of metal sulfide/phosphide heterostructures with optimized d-band center and boosted electrocatalytic oxygen evolution

Abstract

Constructing heterostructures to regulate the electronic structure is an effective strategy for enhancing the oxygen evolution reaction (OER) electrocatalytic activity. Herein, we prepared heterostructured Co₄S₃/CoP₃ (CoPS/NFF) electrocatalysts through a one-step phosphorization and sulfuration process. The synthesized electrode drives an overpotential of 190, 272, and 331 mV at 20, 50, and 100 mA cm⁻² for OER in 1 M KOH alkaline media, respectively. These values outperformed those of monophase Co₄S₃ and CoP₃ as well as the majority of transition metal-based catalysts previously reported. Furthermore, the Density Functional Theory (DFT) calculation results show that charge redistribution occurs at CoPS/NFF heterogeneous interfaces, which facilitates charge transfer and improves catalytic activity. The CoPS/NFF with heterostructure optimizes the adsorption strength of oxygen-containing intermediates (*O, *OH, and *OOH) by appropriately adjusting the d-band center energy level, thereby reducing the energy barrier of OER. This work provides a new perspective on rational design strategies for efficient transition metal-based electrocatalysts by inducing d-band center regulation through the construction of heterostructures.