Cu‐Bi 2 O 3 /g‐C 3 N 4 Single‐Atom Catalysts for Boosting Near‐Infrared Light‐Driven Liquid Biomass Valorization

ABSTRACT A critical obstacle to achieving high overall energy conversion efficiency in mild‐condition photocatalytic biomass upgrading is insufficient exploitation of near‐infrared (NIR) light within solar spectrum. In this study, we report a photocatalyst (CBC‐X) constructed by grafting a copper single atom (Cu SA ) onto Bi 2 O 3 /g‐C 3 N 4 (BC) heterojunction, where Cu SA serves as an electron‐capture center and synergizes with the interfacial built‐in electric field (IEF) to accelerate interfacial carrier redistribution and improve charge utilization. CBC‐2 enables efficient NIR‐light‐driven esterification of liquid biomass into biofuel with a high yield of 98.9%. Additional temperature‐controlled monochromatic irradiation experiments revealed that CBC‐2 maintained a pronounced NIR‐light‐promoted catalytic response, exhibiting approximately 3.91‐ and 5.60‐fold higher average net methyl oleate formation rates than the BC heterojunction under 800 and 980 nm illumination, respectively. Infrared thermal imaging revealed a more pronounced apparent NIR‐induced heating response for CBC‐2, while temperature‐controlled catalytic experiments demonstrated the contribution of thermal conditions to the overall esterification performance. This work encourages the targeted design of a new theoretical foundation and technical pathway for designing NIR‐responsive photocatalysts of high performance, advancing the green valorization of liquid biomass.