In situ growth of bismuth oxybromide/bismuth molybdate 2D/2D Z-scheme heterojunctions with rich interfacial oxygen vacancies for photocatalytic benzylic C(sp3)-H bond activation

Abstract

The selective oxidation of toluene into valuable chemicals via photocatalytic C(sp³)-H bond activation represents a significant, yet challenging process. Here, the in situ construction of bismuth oxybromide/bismuth molybdate (BiOBr/Bi₂MoO₆) 2D/2D Z-scheme heterojunctions featuring interface-induced oxygen vacancies (OVs) is introduced. The optimized BiOBr/Bi₂MoO₆ sample has a remarkable yield rate of benzaldehyde at 2134.28 μmol g^-1 h^-1 under blue LED irradiation, surpassing the performance of BiOBr and Bi₂MoO₆ by 8.1 and 2.9 times, respectively. Insights from density functional theory (DFT) calculations, electron paramagnetic resonance (EPR), and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies highlight the critical role of the Z-scheme electronic configuration and OVs in attaining the superior photocatalytic toluene conversion efficiency. This study advances the photocatalytic conversion of benzaldehyde within an OV-enhanced direct Z-scheme system, facilitating the activation of inert C(sp³)-H bonds, and contributes to the development of high-performance catalysts for sustainable chemical processes.