Directional movement of electron induced by interfacial coupling in CuS@NiCo-LDHs for efficient alkaline oxygen evolution reaction

Abstract

Heterojunction has the characteristics of adjusting catalyst structure, improving oxygen evolution kinetics and breaking the elevated reaction barrier of oxygen evolution process. In this paper, a heterostructure catalyst of NiCo-LDHs nanosheets encapsulated CuS hollow nano-octahedrals has been reported, which has better stability and higher mass transfer efficiency compared with two-dimensional nanosheets. Density functional theory (DFT) calculations indicate that the heterostructure strengthens the orbital hybridization of metal 3d and O 2p, at the same time, the heterointerface coupling induces the directional movement of electrons from NiCo-LDHs to CuS, which together provide abundant high-valence Ni and Co active sites, promote the conversion of *OH to *O species, thus reducing the energy required for the reaction. Hence, CuS@NiCo-LDHs exhibits excellent OER performance and good stability in 1 M KOH. When the current density is 10 mA/cm2, the overpotential and Tafel slope of this catalyst is only 253 mV and 56 mV/dec, respectively. This study furnishes the construction of heterogeneous structures and the catalyst exploitation with serviceable insights.