Surfactants govern the fabrication of sulfur-enriched heterojunction catalysts for highly selective photocatalytic conversion of toluene

Abstract

Photocatalytic selective oxidation of toluene represents a milder and more environmentally friendly strategy for the synthesis of benzaldehyde. In order to enhance catalytic performance, efficient carrier separation and transport are crucial in the photocatalytic process. This study focused on the preparation of ZnS@ZnIn2S4 with sulfur vacancies and heterostructures, combining the advantages properties of ZnS and ZnIn2S4 in photocatalysis. The effects of ZnS and surfactants on the catalytic properties of the composites were studied in depth. Characterization tests revealed that surfactant-modified ZnS@ZnIn2S4 exhibited a higher concentration of sulfur defects, which facilitated electron trapping and promoted photogenerated carrier separation and utilization. Additionally, the present study also demonstrated that the incorporation of ZnS and surfactants could reduce the crystal size of ZnIn2S4, thereby facilitating the exposure of additional active sites. The synergistic effect of the aforementioned advantages enabled toluene to undergo oxidation at a conversion rate of 39% in the presence of oxygen, resulting in the production of benzaldehyde with an exceptional selectivity of 92%. This finding offers valuable insights for future endeavors in designing photocatalytic C-H bond oxidation catalysts.