Polyethyleneimine coated AgInS2 quantum dots for efficient CO2 photoreduction to C2H6

Quantum dots exhibit great potential in photocatalytic CO₂ conversion into value-added fuels to achieve a carbon-neutral society, owing to their unique optical properties and tunable surface chemistry. However, the generation of multi-carbon hydrocarbon products remains a grand challenge. Herein, polyethyleneimine (PEI) coated AgInS₂ quantum dots (AgInS₂@PEI QDs) are designed for the photo-catalytic conversion of CO₂ to C₂ products. It is found that the yield and selectivity of C₂H₆ can be significantly enhanced by regulating the content of Ag and PEI in AgInS₂@PEI QDs. Under the optimal conditions, C₂H₆ yield reaches 63 μmol g^-1, and the electron selectivity is 30.3 %. A mechanistic study reveals that PEI effectively promotes the accumulation of photogenerated electrons, and the CO-enriched local environment caused by Ag boosts CC coupling on asymmetric bimetallic sites. This work offers new insight on the design of efficient quantum dot photocatalysts for CO₂ conversion to C₂ products.