Engineering semiconductor quantum dots for co-upcycling of CO2 and biomass-derived alcohol

Abstract

Utilizing semiconductor quantum dots (QDs) to construct a bifunctional reaction system of coupling CO₂ reduction with biomass valorization represents an appealing approach for the production of usable fuels and value-added chemicals. Herein, we present an efficient cooperative photocatalytic process for simultaneously achieving the reduction of CO₂ to syngas and the oxidation of biomass-derived furfuryl alcohol to furfural and hydrofuroin over SiO₂-supported CdSe/CdS QDs (CdSe/CdS-SiO₂). The type-II band alignment in CdSe/CdS core/shell heterostructures enables effective charge separation and interfacial charge migration concurrently. By further assembly onto spherical SiO₂ support, the optimized CdSe/CdS-SiO₂ composite exhibits remarkably enhanced activities for syngas and furfural/hydrofuroin production, which are 2.3 and 3.5 times higher than those of binary CdSe/CdS core/shell QDs, and 90.4 and 18.5 times higher than those of bare CdSe QDs, along with good stability. In particular, by altering the thickness of CdS shell, the syngas CO/H₂ ratio can be precisely modulated within a wide range (1.6 to 7.1), which serves as a crucial feedstock for the production of liquid fuels. This work is expected to develop core/shell QDs-based photocatalysts for versatile and available photoredox-catalyzed reaction systems that integrate CO₂ valorization with biomass upgrading.