Concurrent Photocatalytic CO₂ Reduction and 1‐Phenylethanol Oxidation Regulated by Chloride Ion‐Capped CdS@Zn_xCd_1‐xS@ZnS QDs

Abstract Solar‐driven photocatalytic CO₂ reduction coupled with the oxidation of organic compounds to value‐added chemicals is a promising strategy, which can utilize both photogenerated electrons and holes. Here, a gradient alloyed CdS@Zn_xCd_1‐xS@ZnS quantum dots (quasi‐Type II band structure) capped with Cl⁻ ligands demonstrate great potential in the simultaneous conversion of CO₂ and 1‐phenylethanol into syngas and pinacol. The passivation with Cl⁻ maximizes the exposure of surface‐active sites and improves their electronic structure, providing a prerequisite for the efficient execution of redox reactions. More importantly, the p–π conjugation between chloride‐ion ligands and the benzene ring provides a bridge for the ultrafast transfer of holes, which greatly promotes the activation of the Cα─H bond in 1‐phenylethanol to release a mass of reactive free hydrogen. This process effectively lowers the thermodynamic energy barrier for CO₂ reduction, even as the excessively high kinetic energy barriers arising from the accumulation of excess protons also enable them to self‐couple, leading to the generation of syngas (CO ≈ 75 mmol g⁻¹ h⁻¹; selectivity ≈ 69.86%). This work provides insights for future artificial photosynthesis to achieve high activity and cost‐effective conversion of CO₂ into storable renewable resources and the co‐production of value‐added substances through synergistic organic oxidation.