Constructing Ag decorated ZnS1-x quantum dots/Ta2O5-x nanospheres for boosted tetracycline removal: Synergetic effects of structural defects, S-scheme heterojunction, and plasmonic effects

Constructing S-scheme charge transfer pathways is often considered to be an efficient strategy for boosting interfacial charge separation for high-performance photocatalysis, especially for ultrawide bandgap tantalum-based semiconductors. In this work, defects-mediated S-scheme ZnS 1-x quantum dots (QDs)/Ta 2 O 5-x composites decorated with Ag were prepared by the modified solvothermal and photoreduction methods and employed for visible-light photocatalytic toxic tetracycline degradation. Compared with commercial Ta 2 O 5 , pristine Ta 2 O 5-x microspheres, and ZnS 1-x QDs , the prepared Ag/ZnS 1-x /Ta 2 O 5-x -1.0% composite showed the highest visible-light photocatalytic performance, and the corresponding reaction rate constant reached as high as approximately 0.02605 min −1 , which was 5.97 times of ZnS 1-x QDs, 2.63 times of Ta 2 O 5-x , and far better than that of commercial Ta 2 O 5 . The main reactive species, photocatalytic mechanism and degradation pathways were also studied. The highly enhanced photocatalytic performance of the Ag/ZnS 1-x quantum dots/Ta 2 O 5-x composites could be mainly attributed to the formation of Ag modified S-scheme heterostructures and highly increased surface areas. Current work indicates a high-performance tantalum-based composite for dealing with persistent organic pollutants.