Abstract: The development of a bifunctional photocatalyst that can be utilized for both energy conversion and environmental remediation is of great practical significance. In addition, an S-scheme charge transfer process can assist a photocatalyst in efficiently separating photoexcited electrons and holes while maintaining the strong reducibility and oxidizability of the former and the latter, respectively. We developed a bifunctional S-scheme hybrid photocatalyst comprising CdS nanorods and BiOIO₃ (BIO) nanosheets for efficient antibiotic degradation and cocatalyst- and sacrificial reagent-free CO₂ reduction. The combination of visible-light-responsive one-dimensional (1D) CdS and UV-light-responsive 2D BIO resulted in a CdS/BIO hybrid photocatalyst with effective 1D/2D (line) interfacial contact and a broadened optical absorption range. Notably, the CdS/BIO hybrid exhibited exceptional diclofenac degradation and mineralization as well as outstanding CO₂ reduction activity for CO production, with 95.4% CO selectivity over H₂ production. The exceptional performance of the hybrid catalyst is primarily attributed to the accelerated photoexcited charge transfer caused by the 1D/2D line interfacial contact and the high charge separation and strong redox power of the separated charges, both of which stem from the effective S-scheme charge transfer process. In addition, photocorrosion of CdS was substantially mitigated, resulting in the high photocatalytic performance of the hybrid catalyst even after repeated test runs. This study provides insight into the rational design of bifunctional S-scheme hybrid photocatalysts for CO₂ reduction and pollutant degradation.

Key words: CdS, BiOIO₃, Bifunctional photocatalyst, S-scheme mechanism, Antibiotic degradation, CO₂ reduction