Abstract
The deep oxidation of toluene is recognized as a major challenge for photocatalytic oxidation of toluene. Herein, we introduced oxygen vacancies into CeO2 nanosheets through novel anion-removal of Ce-LDH, with the calcining temperatures of 750, 850, 950 °C. The photocatalytic toluene performance was ordered by CeMO-850 > CeMO-750 > CeMO-950, and CeMO-850 had better activity than P25, common CeO2, and CeO2-H2. Different reaction pathways were founded on CeMO photocatalysts, i.e., on CeMO-950 and CeMO-750, the cresol and hydroquinone intermediates were observed, which hindered toluene adsorption/activation and were hard to deep-mineralization. Whereas, more benzoic acid, open-loop oxygen-containing intermediates were observed on CeMO-850, which were resulted from its oxygen vacancies (Ov), i.e., surface Ov and Ce~(3+) were beneficial for toluene adsorption, B acid sites and active radicals' generation, respectively, and bulk Ov were helpful for oxygen mobility and efficient deep-mineralization. The mechanism of Ov generation and toluene degradation were proposed.
NSTL