Interfacial Heterojunction Engineering for Modulating Charge Dynamics in Photocatalytic CO2 Reduction

The development of efficient and metal-free photocatalysts for the CO2 reduction reaction remains a significant challenge. Herein, a novel metal-free photocatalyst is constructed by anchoring black phosphorus quantum dots (BPQDs) onto boron nitride nanofibers (BNNFs) to form an atomic-level charge transport pathway. This unique zero-dimensional/one-dimensional heterostructure exhibits a remarkable photocatalytic CO2-to-CO conversion activity, achieving an evolution rate approximately 12 times higher than that of pristine BNNF. Comprehensive experimental characterizations and density functional theory calculations collaboratively reveal the mechanism behind this enhancement: the BPQDs not only serve as active sites for CO2 activation but also establish rapid charge-transfer channels. Furthermore, the modified electronic structure effectively lowers the energy barrier for the key *COOH intermediate formation and facilitates the desorption of *CO, thus boosting the overall reaction kinetics. This work opens a new horizon for exploring delicate metal-free hybrid systems at the atomic scale to modulate the charge kinetics and energy barrier toward solar fuel production.