Solar-Driven Highly Effective Biomass-Derived Alcohols C–C Coupling Integrated with H₂ Production by CdS Quantum Dots Modified Zn₂In₂S₅ Nanosheets

The integration of solar-driven H2 evolution with the selective conversion of biomass-derived alcohols into value-added chemicals has gained significant attention for full use of electrons and holes. We develop a dual-functional photocatalyst for highly selective oxidation of the Cα–H bond of benzyl alcohol to C–C coupled products (hydrobenzoin and deoxybenzoin), in cooperation with H2 evolution, using point-to-face interface engineering by decorating CdS quantum dots on Zn2In2S5 nanosheets (CdS QDs/Zn2In2S5 NS). The CdS QDs/Zn2In2S5 NS exhibit a high H2 evolution rate of 13 mmol g–1 h–1 and C–C coupled products formation rate of 10.8 mmol g–1 h–1 with 96.3% selectivity. Benzyl alcohol conversion achieves 91% with an 89% yield of C–C coupled products in gram-scale. The introduction of CdS enhances the interfacial contact, facilitating the efficient spatial separation of photogenerated electron–hole pairs and providing active sites for H2 evolution. In situ characterization and DFT calculation reveal that the carbon-centered radical •CH(OH)C6H5, generated by abstracting the Cα–H bond of benzyl alcohol, is the reactive intermediate in the photocatalytic C–C coupled process.