Facile fabrication of self-supporting porous CuMoO₄@Co₃O₄nanosheets as a bifunctional electrocatalyst for efficient overall water splitting

Abstract

Research shows that redox complementarity and synergism among the ingredients of heterogeneous catalysts can enhance the performance of the catalyst. In this research, a porous CuMoO₄@Co₃O₄ nanosheet electrocatalyst is prepared, which is uniformly decorated on nickel foam (NF) by hydrothermal reactions and the impregnation method. The CuMoO₄@Co₃O₄ is an efficient bifunctional catalyst with prominent electrocatalytic activity and durability. It requires overpotentials of only 54 and 251 mV to obtain current densities of 10 and 50 mA cm^-2 for the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER) in 1.0 mol L^-1 KOH, corresponding to Tafel slope values of 98.8 and 87.4 mV dec^-1, respectively. Furthermore, the CuMoO₄@Co₃O₄ shows excellent stability of 120 h chronopotentiometry at a current density of 100 mA cm^-2 for the HER/OER. Notably, an alkaline electrolyzer (with CuMoO₄@Co₃O₄ as the HER and OER electrodes) can deliver a current density of 10 mA cm^-2 at a low voltage of 1.51 V. The catalytic activity of CuMoO₄@Co₃O₄ can be attributed to the structure of the porous nanosheets and the synergistic effect between CuMoO₄ and Co₃O₄.