Sulfur-vacancy-rich ZnS/CdIn2S4 heterojunction for efficient photocatalytic selective oxidation of toluene to benzaldehyde

The conversion of the volatile organic pollutant to industrially valuable chemicals using photocatalysis is a promising endeavor. Herein, ZnS/CdIn 2 S 4 heterojunction with rich sulfur vacancy was constructed via a simple one-pot method for the selective photocatalytic oxidation of toluene to benzaldehyde . ZnS/CdIn 2 S 4 has a suitable band gap and valence band position, thus possessing a mild oxidation ability to generate benzaldehyde while avoiding excessive oxidation. In addition, the presence of tightly bound contact interfaces and sulfur vacancy in ZnS/CdIn 2 S 4 heterojunction facilitates the rapid separation of photogenerated electron-hole. These characteristics of the heterojunction synergistically promoted the selective photocatalytic oxidation of toluene, resulting in ZnS/CdIn 2 S 4 exhibiting the highest benzaldehyde production rate (1025 μmol g −1  h −1 ) and the highest conversion rate (13.7%), which were 93.1 and 56.9 times higher than those of ZnS and CdIn 2 S 4 , respectively. Furthermore, a possible response mechanism has been suggested based on a series of experiments. This study provides new insights into the combination of volatile organic pollutant degradation and high-value chemicals production.