Designing a novel dual Z-scheme Bi2S3-ZnS/MoSe2 photocatalyst for photocatalytic reduction of Cr(VI)

High toxic Cr(VI) has great harm to the environment and human body. The structural design of photocatalyst is an effective strategy to improve their photocatalytic activities. The Z-scheme heterojunction not only has excellent performance in the separation of photogenerated carriers, but also retains the strong redox ability of the catalyst. In this study, a dual Z-scheme Bi2S3-ZnS/MoSe2 (BZM) photocatalyst with ZnS and Bi2S3 deposited on the surface of 2D MoSe2 nanosheets is designed and prepared for the photocatalytic reduction of Cr(VI). The experimental results prove that BZM-0.15 shows the most excellent photocatalytic performance with the reduction efficiency of more than 95.4%, which is much higher than Bi2S3 (45.4%), ZnS (47.7%) and MoSe2 (59.6%). Besides, BZM-0.15 also has good cycle stability. The Z-scheme heterojunction in Bi2S3-ZnS/MoSe2 plays a vital role for enhancing the visible light absorption and efficiently promoting the photogenerated carriers transfer by providing double charge transfer channels. This research will offer a new method of designing and synthesizing a novel dual Z-scheme photocatalyst for effective photocatalytic reduction of Cr(VI).