S-Scheme Bi₂S₃/CdS Nanorod Heterojunction Photocatalysts with Improved Carrier Separation and Redox Capacity for Pollutant Removal

Constructing step scheme (S-scheme) heterojunctions makes it possible for promoting the separation and transfer of photoinduced carriers, as well as maintaining strong photoredox capacities. Herein, S-scheme Bi2S3/CdS heterojunctions were designed and constructed by the in situ substitution of Bi3+ on CdS nanorods. The S-scheme 10%-Bi2S3/CdS heterojunction with intense interfacial contacts shows not only an optimal photoreduction rate toward Cr(VI) (3.18 and 7 times that of pure CdS and Bi2S3, respectively) but also a high photodegradation rate of ciprofloxacin (1.94 and 8.75 times that of pure CdS and Bi2S3, respectively). Meanwhile, the S-scheme 10%-Bi2S3/CdS heterojunction could efficiently prevent itself from photoetching. It is confirmed that the S-scheme 10%-Bi2S3/CdS heterojunction is produced by a built-in electric field between CdS and Bi2S3, which not only improves the charge transfer and separation efficiencies but also maintains strong redox capacities. The present study will provide distinguished insight into fabricating an S-scheme heterojunction with strong photoredox capabilities for the removal of pollutants.