High photocatalytic and photoelectrochemical performances of the CuSe/MoSe2 2D/2D face-to-face heterojunction photocatalyst

Abstract Photocatalysis and photoelectrochemistry are effective approaches to solve the energy and environmental crises. The suitable catalyst is the key for photocatalysis and photoelectrochemistry. Metal selenides have good prospects for their narrow band gap, low internal resistance, and related high photoelectric performance. In this work, a novel CuSe/MoSe2 2D/2D face-to-face heterojunction photocatalyst was obtained through a simple hydrothermal route. These CuSe/MoSe2 2D/2D heterojunction photocatalysts show excellent performance in photocatalytic degradation and photoelectrochemistry. With an optimized CuSe loading ratio of 2.5%, the heterojunction photocatalyst displays an improved degradation rate by 4.5 times and increased photocurrent by 7.6 times than the pristine MoSe2. The large improvement in photocatalysis and photoelectrochemistry can be ascribed to the 2D/2D face-to-face contact between MoSe2 nanoplates and CuSe nanosheets. Given this mode, the interface between CuSe and MoSe2 can be maximized, and good binding can be obtained. The electrochemical impedance and the fluorescence emission spectroscopic methods confirm that the internal resistance is reduced, whereas the separation efficiency is improved. This work demonstrates the prospect of metal selenides used in environmental treatment and hydrogen energy utilization.