Anchoring Bi2S3 quantum dots on flower-like TiO2 nanostructures to boost photoredox coupling of H2 evolution and oxidative organic transformation

The rational integration of semiconductor quantum dots (QDs) with anatase TiO 2 nanostructures is a promising strategy to develop efficient photocatalysts. Herein, Bi 2 S 3 QD/TiO 2 photocatalyst was constructed by controllably depositing Bi 2 S 3 QDs on flower-like TiO 2 nanostructures and used for the photocatalytic redox-coupling reaction of H 2 evolution and oxidative transformation of benzyl alcohol. The abundant amino groups in TiO 2 nanostructures served as the anchoring sites for uniform growth of Bi 2 S 3 QDs. The anchoring of Bi 2 S 3 QDs onto TiO 2 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 Bi 2 S 3 QD/TiO 2 photocatalyst exhibited a favorable performance in the redox-coupling reaction, providing the high production rates of H 2 up to 4.75 mmol·g cat −1 ·h −1 and benzaldehyde up to 6.12 mmol·g cat −1 ·h −1 , 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.