Double bismuth-based Bi2S3/Bi2MoO6 S-scheme heterojunction for ultrafast photocatalytic removal of Cr(VI)

The mild, fast and green removal of hexavalent chromium (Cr(VI)) from wastewater has already attracted extensive attention due to the severe acute toxicity and carcinogenicity of Cr(VI). At present work, Bi2S3/ Bi2MoO6 S-scheme heterojunctions were constructed by facile solvothermal assembly and in situ anion exchange methods for visible light-driven efficient photocatalytic removal of Cr(VI). The structure-activity relationship, photoelectrochemical properties, and density functional theory (DFT) calculations revealed that the controllable construction of the heterostructure significantly expanded the light response range and remarkably enhanced the light absorption capacity. In particular, the unique charge transfer mechanism of this S-scheme heterojunction is conducive to promoting efficient separation of photogenerated charges and thus enhancing the photocatalytic performance. The results show that the total efficiency of Cr(VI) removal by the developed Bi2S3/Bi2MoO6 heterojunction under visible light irradiation is 98.5% within 6 min, with a k value of 0.466 min-1. This work provides a new route with enormous promise to construct bismuth-based S-scheme heterojunction photocatalysts for clean and efficient environmental remediation.