Ce³⁺-Doped Cs₃Bi₂Br₉ for Photocatalytic Selective Oxidation of Alcohols to Aldehydes/Ketones

Herein, Ce³⁺-doped bismuth-based perovskite Cs₃Bi₂Br₉ (Ce-CBB) photocatalysts were developed as heterogeneous photocatalysts for the highly selective oxidation of alcohols to the corresponding aldehydes and ketones. An in-depth analysis of the crystal structure and electronic structure variations induced by Ce³⁺ doping was performed by a series of spectroscopic and photoelectrochemical methods. The evaluation of the photocatalytic performance of Ce-CBB in the oxidation of alcohols showed that Ce³⁺ doping markedly enhanced the photocatalytic activity, raising the benzaldehyde production rate from 60.74 to 99.31 mmol·g^-1·h^-1. Furthermore, a total of 29 alcohols were oxidized to their corresponding aldehydes and ketones with excellent conversion (>95%) and selectivity (>95%). Finally, a series of control experiments, spectroscopic studies, isotope labeling experiments, and density functional theory (DFT) thermodynamic calculations were carried out to elucidate the reaction mechanism, wherein reactive oxygen species (ROS) were proven to play dominant roles in the oxidation accompanied by a minor contribution from H₂O in the system.