Cooperative Syngas Production and C-N Bond Formation in One Photoredox Cycle

Solar-driven syngas production by CO₂ reduction provides a sustainable strategy to produce renewable feedstocks. However, this promising reaction often suffers from tough CO₂ activation, sluggish oxidative half-reaction kinetics and undesired by-products. Herein, we report a function-oriented strategy of deliberately constructing black phosphorus quantum dots-ZnIn₂ S₄ (BP/ZIS) heterostructures for solar-driven CO₂ reduction to syngas, paired with selectively oxidative C-N bond formation, in one redox cycle. The optimal BP/ZIS heterostructure features the enhanced charge-carrier separation and enriched active sites for cooperatively photocatalytic syngas production with a tunable ratio of CO/H₂ and efficient oxidation of amines to imines with high conversion and selectivity. This prominent catalytic performance arises from the efficient electronic coupling between black phosphorus quantum dots and ZnIn₂ S₄ , as well as the optimized adsorption strength for key reaction intermediates, as supported by both experimental and theoretical investigations. We also demonstrate a synergistic interplay between CO₂ reduction and amine dehydrogenation oxidation, rather than simply collecting these two single half-reactions in this dual-functional photoredox system.