Facile fabrication of self-supporting porous CuMoO 4 @Co 3 O 4 nanosheets 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 CuMoO 4 @Co 3 O 4 nanosheet electrocatalyst is prepared, which is uniformly decorated on nickel foam (NF) by hydrothermal reactions and the impregnation method. The CuMoO 4 @Co 3 O 4 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 CuMoO 4 @Co 3 O 4 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 CuMoO 4 @Co 3 O 4 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 CuMoO 4 @Co 3 O 4 can be attributed to the structure of the porous nanosheets and the synergistic effect between CuMoO 4 and Co 3 O 4 .