Dual Functions of O-Atoms in the g-C₃N₄/BO_0.2N_0.8Interface: Oriented Charge Flow In-Plane and Separation within the Interface to Collectively Promote Photocatalytic Molecular Oxygen Activation

The photocatalytic performance of two-dimensional materials is largely limited by the fast recombination of photogenerated charges. Herein, we design and fabricate a novel g-C3N4/BO0.2N0.8 van der Waals heterostructure to realize oriented charge flow in-plane and separation within the interface. On one hand, a B-C bond forms within the g-C3N4/BO0.2N0.8 interface after the introduction of O atoms. The B-C bond as the mediator bridges g-C3N4 and BO0.2N0.8 sides to enhance the effective separation of photogenerated charges. On the other hand, the existence of O atoms promotes the formation of a B-O-O-B intermediate to realize that molecular oxygen can directionally obtain electrons from the surface to generate O2-. As a result, BO0.2N0.8 instead of g-C3N4 is considered to be the main reaction side, and the energy barrier of NO3- generation is significantly decreased. The NO removal performance of g-C3N4/BO0.2N0.8 is enhanced and the NO2 generation is effectively controlled compared with that of g-C3N and g-C3N4/BN. This work could provide an effective and facile strategy to tune oriented charge transfer.