Amorphous co-doped MoSex effectively enhances photocatalysis in visible light

Abstract

Molybdenum selenide has great potential for the degradation of water pollutants, but its performance is limited by the active sites and recombination of photogenerated electron–hole pairs. In this study, an amorphous co-doped MoSe_x (Co-MoSe_x) sample was synthesized by a low-temperature hydrothermal method. Three types of unsaturated Se–Se bonds were found in Co-MoSe_x by Raman spectroscopy: bridging diselenide, shared diselenide, and terminal diselenide. Photocatalytic experimental results revealed that the degradation rate of Co-MoSe_x to methylene blue was 96.3%, the degradation rate of amorphous MoSe_x (a-MoSe_x) was 61.6%, and the degradation rate of crystalline molybdenum selenide (c-MoSe₂) was 23.2%. Furthermore, it was found that the band gap of the Co-MoSe_x photocatalyst was reduced by 0.15 eV compared to the a-MoSe_x photocatalyst. The photocatalytic activity of the co-doped MoSe_x was enhanced by increasing the unsaturated Se atom active sites, reducing the recombination of photogenerated electron–hole pairs, and improving light utilization.