Modulating heterointerfaces of tungsten incorporated CoSe/Co₃O₄as a highly efficient electrocatalyst for overall water splitting

Electrochemical water-splitting is emerging as a promising pathway to produce pure and green hydrogen. However, the sluggish kinetics of the oxygen evolution reaction (OER) and slow reaction rate of the hydrogen evolution reaction (HER) remain challenging issues. The state-of-the-art Pt and RuO2/IrO2 electrocatalysts demonstrate excellent HER and OER performance. However, the scarcity and high cost hinder their practical applications. Herein, we present a novel approach to design a WCoSe/WCo3O4 heterostructure and use it as an effective bifunctional electrocatalyst for overall water-splitting. The synergistic effect of W and Co metal cations in the heterogeneous phase of Se and O anions could increase the charge transfer and electronic modulation of the material which could improve the catalytic activities. The water electrolysis device with the WCoSe/WCo3O4 heterostructure as a bifunctional catalyst required a small cell voltage of ∼1.49 and 1.66 V at current densities of 10 and 100 mA cm-2. Furthermore, the water-splitting cell displayed an exceptional durability of 100 h, surpassing the state-of-the-art Pt/C‖RuO2 electrolyzer. This work offers a promising approach to construct novel 3D heterostructure electrocatalysts, which would be suitable for various energy conversion applications.