Co₃O₄/Zn-Co-Mo Nanomaterials and Their Applications in Supercapacitors and Electrocatalysis Hydrogen Evolution Reaction

Mixed transition metal compounds with abundant more active sites are attractive to supercapacitors and electrochemical water splitting. In this work, the Co₃O₄/Zn-Co-Mo/NF composite is prepared by a hydrothermal method and thermal annealing. The Zn-Co-Mo nanosheet arrays are synthesized on nickel foam (NF) to form a three-dimensional (3D) network to take advantage of the electrical conductivity and viscosity of NF. Co₃O₄ is produced directly in the 3D microchannels to achieve a large energy density and robust stability. In the test of the supercapacitor performance, the specific capacitance of Co₃O₄/Zn-Co-Mo/NF is 2169 F g^-1 at a current density of 1 A g^-1. In addition, excellent long-term cycling stability is observed as manifested by specific capacitance retention of 85% after 4,000 cycles at a current density of 25 A g^-1. As a catalyst in the hydrogen evolution reaction (HER), Co₃O₄/Zn-Co-Mo/NF shows an overpotential of 128 mV at 10 mA cm^-2. Our results confirm the dual functionality of the materials which have promising potential in energy storage and generation applications. 
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