Enabling Visible‐Light‐Driven Selective CO2 Reduction by Doping Quantum Dots: Trapping Electrons and Suppressing H2 Evolution

Abstract Quantum dots (QDs), a class of promising candidates for harvesting visible light, generally exhibit low activity and selectivity towards photocatalytic CO 2 reduction. Functionalizing QDs with metal complexes (or metal cations through ligands) is a widely used strategy for improving their catalytic activity; however, the resulting systems still suffer from low selectivity and stability in CO 2 reduction. Herein, we report that doping CdS QDs with transition‐metal sites can overcome these limitations and provide a system that enables highly selective photocatalytic reactions of CO 2 with H 2 O (100 % selectivity to CO and CH 4 ), with excellent durability over 60 h. Doping Ni sites into the CdS lattice leads to effective trapping of photoexcited electrons at surface catalytic sites and substantial suppression of H 2 evolution. The method reported here can be extended to various transition‐metal sites, and offers new opportunities for exploring QD‐based earth‐abundant photocatalysts.