Achieving High Selectivity in Photocatalytic Oxidation of Toluene on Amorphous BiOCl Nanosheets Coupled with TiO2

Theinert C(sp (3))-H bond andeasy overoxidation of toluene make the selective oxidation of tolueneto benzaldehyde a great challenge. Herein, we present that a photocatalyst,constructed with a small amount (1 mol %) of amorphous BiOCl nanosheetsassembled on TiO2 (denoted as 0.01BOC/TiO2),shows excellent performance in toluene oxidation to benzaldehyde,with 85% selectivity at 10% conversion, and the benzaldehyde formationrate is up to 1.7 mmol g(-1) h(-1), which is 5.6 and 3.7 times that of bare TiO2 and BOC,respectively. In addition to the charge separation function of theBOC/TiO2 heterojunction, we found that the amorphous structureof BOC endows its abundant surface oxygen vacancies (Ov), which canfurther promote the charge separation. Most importantly, the surfaceOv of amorphous BOC can efficiently adsorb and activate O-2, and amorphous BOC makes the product, benzaldehyde, easily desorbfrom the catalyst surface, which alleviates the further oxidationof benzaldehyde, and results in the high selectivity. This work highlightsthe importance of the microstructure based on heterojunctions, whichis conducive to the rational design of photocatalysts with high performancein organic synthesis.