Coupling interface constructions of FeOOH/NiCo ₂ S ₄ by microwave‐assisted method for efficient oxygen evolution reaction

Abstract

Abstract The oxygen evolution reaction (OER) with slow kinetics is the rate‐limiting step of electrochemical water splitting. A reasonable construction of interface nanostructures is the key to improving the OER efficiency and durability of non‐noble metal electrocatalysts. In this study, a FeOOH/NiCo 2 S 4 core–shell nanorod array with abundant heterogeneous interfaces and high density of active sites was successfully prepared by a microwave‐assisted method. Experimental research and theoretical calculations show that the abundant strong coupling Ni/Co–S–Fe interface helps in adjusting the electronic structure of the material surface, optimizing the adsorption energy of the intermediate, and realizing an efficient catalytic process. The as‐synthesized FeOOH/NiCo 2 S 4 /NF composite electrode exhibited lower overpotential (198 mV) and Tafel slope (62 mV·dec −1 ) at a current density of 10 mA·cm −2 and excellent stability (approximately 100% retention after 100 h) than the NiCo 2 S 4 /nickel foam (NF). In conclusion, constructing heterojunctions with complementary active materials is an effective strategy to design efficient and robust OER electrocatalysts.