Ce Doping Boosts the Photocatalytic Activity of Ultrathin Bi₂MoO₆ Nanosheets for Toluene Selective Oxidation

Abstract

The generation of reactive oxygen species (ROS) from O 2 is a critical step to boost the performance of photocatalytic toluene oxidation. However, the production of ROS is greatly limited by the serious recombination of charge carriers and the lack of O 2 adsorption sites. In this work, Ce-doped Bi 2 MoO 6 ultrathin nanosheets with rich oxygen defects are prepared by a one-step hydrothermal method. The ultrathin structure promotes the longitudinal transport of carriers to the surface. The introduction of Ce ions generates both Ce 3+ /Ce 4+ redox ion pairs and oxygen defects in Bi 2 MoO 6 , where the former promotes the transfer of photogenerated electrons and the latter enhances the adsorption of O 2 , thereby producing more superoxide radicals (•O 2 − ). Attributed to these advantages, Ce-doped Bi 2 MoO 6 ultrathin nanosheets exhibit excellent photocatalytic activity for toluene selective oxidation. The toluene conversion rate is 4422 μmol•g −1 •h −1 . The selectivity values of benzaldehyde and benzyl alcohol are 84.7 and 15.3%, respectively. In addition, the mechanism of photocatalytic selective oxidation of toluene is further explored through a series of experiments.

Toluene Oxidation: CO2 vs Benzaldehyde: Current Status and Future Perspectives

“…Zeng et al 71 studied the effect that doping Ce over Bi 2 MoO 6 could result in the photocatalytic activity of the catalyst. The doping of Ce introduced the redox ion pairs Ce 3+ /Ce 4+ and generated oxygen defects in Bi 2 MoO 6 responsible for increasing the activity of the catalyst in the presence of O 2 since it allows a better activation of the oxidant.…”