Photoredox-catalyzed coupling of CO2 reduction and amines oxidation by Cu doped CdS quantum dots

Solar-driven carbon dioxide (CO2) reduction integrated with selective organic synthesis proposes a sustainable paradigm to achieve carbon neutrality concomitantly with value-added fuels and chemicals production. Here, we report the synergistic coupling reaction of CO2 reduction and amines oxidation to syngas and secondary amines over Cu doped CdS quantum dots (Cu:CdS QDs) under visible light. This system is compatible with various amines to afford the corresponding secondary amines with outstanding selectivity. Notably, the syngas CO/H2 ratio can be obtained in a window from 1:2 to 2:1 by altering the Cu doping content. Mechanistic studies unveil that doped Cu not only improves the charge separation efficiency, but also serves as active sites for the adsorption/activation of CO2, thus adjusting the syngas ratio. This work is envisaged to enable a viable strategy for the rational design of transition metal-doped semiconductor QDs toward the co-production of syngas and high-value chemicals in one photoredox cycle.