Hydrothermally synthesized mixed metal oxide nanocomposites for electrochemical water splitting and photocatalytic hydrogen production

Abstract

Here, mixed metal oxide composites CuO/NiO/ZrO2 (CNZr) were fabricated by a facile hydrothermal route, and their electrochemical water splitting, and photocatalytic hydrogen production were further investigated. The CNZr600 composite exhibited the H2 generation rate of 14.27 mmol g−1 h−1, which is greater than that of the CNZr400, CNZr500 composites. The mixed metal oxide composite of CNZr600/NF with numerous catalytically active centers and charge transfer ability furnished minor overpotentials of 218 mV and 372 mV for HER and 400 mV and 540 mV for OER at 10 and 50 mA cm−2, respectively, in potassium hydroxide electrolyte. The alkaline electrolyzer designed by CNZr600/NF requires an appealing operating potential of 1.69 V for efficient H2 production. In addition, electrochemical impedance spectroscopy measurements showed a reduced impedance response for the composites, which was dominated by the relaxation of the intermediate frequency connected with the adsorption of the intermediate. Furthermore, the superior catalytic activities of the mixed metal oxide composites were attributed to their structural properties, high electroactive surface areas, fast electron transport kinetics, and good chemo-electrical bonding between CuO, NiO, and ZrO2. These consequences provide a new vision for the design of mixed metal oxide composite catalysts for low-cost H2 production.