Interfacial Br N bond enables charge shuttle in coulomb blockade Cs3Bi2Br9 perovskite nanocrystals via g-C3N4 heterogenization for selective toluene oxidation

Heterojunction catalysts exhibit great potential in photocatalysis owing to their superior charge separation efficiency. However, precise regulation of interfacial electronic structures and their impact on photocatalytic reactions remains challenging. Here, we present an effective strategy involving accurate control of carrier dynamics through the rational design of interfacial covalent bonds. This strategy achieves high selectivity and productivity in toluene photo-oxidation, with a remarkable C6H5-CHO selectivity of 98.1 % and a conversion ratio of 55.2 %. Our findings reveal that the dot-on-plate Cs3Bi2Br9@g-C3N4 heterojunction, featuring an interfacial Br-N covalent bond and an internal electric field, promotes efficient charge transfer. Moreover, utilizing quasi-in situ EPR, in-situ ATR-FTIR spectra, and DFT calculations, we demonstrate that the interfacial Br-N covalent bond efficiently adsorbs/activates molecules, significantly accelerating the overall reaction and enhancing selectivity. This work underscores the importance of electronic structures based on covalent bond-bridged heterojunctions, offering insights for designing high-performance photocatalysts in organic synthesis.