Designing and fabricating a CdS QDs/Bi2MoO6 monolayer S-scheme heterojunction for highly efficient photocatalytic C2H4 degradation under visible light.

Achieving efficient photocatalytic degradation of atmospheric volatile organic compounds (VOCs) under sun-light is still a significant challenge for environmental protection. The S-scheme heterojunction with its unique charge migration route, high charge separation rate and strong redox ability, has great potential. However, how to regulate interfacial charge transfer of the S-scheme heterojunction is of significant importance. Here, density functional theory (DFT) calculations were first conducted and predicted that an S-scheme heterojunction could be formed in the CdS quantum dots/Bi 2 MoO 6 monolayer system. Subsequently, this novel heterojunction is constructed by in-situ hydrothermal synthesis of CdS quantum dots on monolayer Bi 2 MoO 6. Under visible-light, this novel S-scheme system gives a high-efficiency photocatalytic degradation rate (6.04 × 10−2 min−1) towards C 2 H 4 , which is 30.3 times higher than that of pure CdS (1.99 × 10−3 min−1) and 41.7 times higher than pure Bi 2 MoO 6 (1.45 × 10−3 min−1). Strong evidence for the S-scheme charge transfer path is provided by in-situ XPS, PL, TRPL and EPR. [Display omitted] • A novel S-scheme CdS QDs/Bi 2 MoO 6 monolayer photocatalyst was synthesized. • This S-scheme heterojunction shows excellent activities for C 2 H 4 photodegradation. • The reaction mechanism of C 2 H 4 photooxidation was comprehensively investigated. [ABSTRACT FROM AUTHOR]