Anchoring BiS quantum dots on flower-like TiO nanostructures to boost photoredox coupling of H evolution and oxidative organic transformation.

The rational integration of semiconductor quantum dots (QDs) with anatase TiO nanostructures is a promising strategy to develop efficient photocatalysts. Herein, BiSQD/TiO photocatalyst was constructed by controllably depositing BiS QDs on flower-like TiO nanostructures and used for the photocatalytic redox-coupling reaction of H evolution and oxidative transformation of benzyl alcohol. The abundant amino groups in TiO nanostructures served as the anchoring sites for uniform growth of BiS QDs. The anchoring of BiS QDs onto TiO nanostructures not only enhanced the photoabsorption ability and the photogenerated charge separation efficiency but also afforded powerful photogenerated charge carriers and abundant active sites for the photocatalytic reaction. As a result, the BiSQD/TiO photocatalyst exhibited a favorable performance in the redox-coupling reaction, providing the high production rates of H up to 4.75 mmol·g·h and benzaldehyde up to 6.12 mmol·g·h, respectively, as well as an excellent stability in the long-term photocatalytic reaction. Meanwhile, a trace amount of water in the reaction system could act as a promoter to accelerate the photocatalytic redox-coupling reaction. The photocatalytic mechanism following S-scheme heterojunction was proposed according to the systematic characterizations and experimental results. This work offers some insight into the rational construction of efficient and cost-effective photocatalysts for the conversion of solar to chemical energy.