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 useable 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 a 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 the CdS shell, the syngas CO/H₂ ratio can be precisely modulated within a wide range (1.6 to 7.1), which serves as crucial feedstock for the production of liquid fuels. This work is expected to develop core/shell QD-based photocatalysts for versatile and available photoredox-catalyzed reaction systems that integrate CO₂ valorization with biomass upgrading.