Fabrication of a Z-scheme MoS₂/CuO heterojunction for enhanced 2-mercaptobenzothiazole degradation activity and mechanism insight

A Z-scheme MoS2/CuO photocatalyst is successfully developed using a hydrothermal and calcination method, which has excellent activity (96%) in the degradation of 2-mercaptobenzothiazole (MBT) under visible light irradiation. The reaction rate constants of MBT degradation on the MoS2/CuO heterojunction are 8 and 6 times higher than those of pure MoS2 and the original CuO, respectively. The as-prepared photocatalyst was characterized using XRD, SEM, XPS and electrochemistry measurement. From the experimental results, the significantly enhanced photocatalytic activity is mainly ascribed to the formation of a Z-scheme heterostructure between MoS2 nanosheets and flower spherical CuO, effectively improving the separation efficiency of photogenerated carriers. What is remarkable is that the Z-scheme electron transfer process leads to a large accumulation of photogenerated electrons and holes, improving the oxidation and reduction properties of CuO and MoS2. Moreover, an intensive study of the mechanism has proved that holes, superoxide radicals and hydroxyl radicals are all active substances in the degradation process. This study opens up a new way to devise novel and highly efficient MoS2-based photocatalysts for the degradation of organic pollutants.