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

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.