Transition metal Co induce CoSe2/NiWSe2 interface structural reorganization for efficient oxygen evolution reaction and urea oxidation reaction

Abstract

Urea-containing wastewater has become an increasingly serious environmental and energy problem. The use of electrochemical urea oxidation reaction (UOR) technology to treat wastewater containing urea has gained considerable significance. The regulation of the composition and electronic properties of the catalyst by doping transition metal elements is crucial for the development of oxygen evolution reaction (OER) and UOR catalysts with high catalytic activity. In this paper, WSe2, CoSe2, NiWSe2 and CoSe2/NiWSe2 were synthesized by hydrothermal method combined with annealing treatment. Compared with WSe2, CoSe2, and NiWSe2, the OER and UOR catalytic activity of CoSe2/NiWSe2 are significantly improved. For OER, a low overpotential of 1.44 V is all that is needed to reach a current density of 10 mA cm−2. The overpotential of UOR is only 1.32 @ 10 mA cm−2, and it can still maintain excellent electrochemical stability after 30 h. The electronic structure of CoSe2/NiWSe2 is changed by the incorporation of Co, thereby improving the conductivity and accelerating the reaction kinetics. CoSe2 particles are uniformly distributed on the layered NiWSe2 nanosheets, which promotes the charge transfer and synergistic effect at the interface between CoSe2 and NiWSe2. The nanoflower-like structure with thin edges enriches the active sites of CoSe2/NiWSe2. Therefore, the transition metal element doping technology can provide a new method for the development of efficient OER and UOR electrocatalysts and provide a new way to reduce the overall energy consumption during urea degradation.