Efficient photocatalytic toluene degradation over heterojunction of GQDs@BiOCl ultrathin nanosheets with selective benzoic acid activation

Photocatalytic toluene degradation has attracted tremendous attention because of the growing environmental problem. However, conventional photocatalytic materials used for toluene degradation usually suffer from low carrier separation efficiency and poor stability which will degrade the catalytic performance. Herein, we report the synthesis of a novel heterostructure of GQDs@BiOCl ultrathin nanosheets where the GQDs can rapidly capture and transport photogenerated electrons for effective charge separation, promoting the generation of more reactive oxygen species (·O2- and ·OH radicals) for toluene degradation. In situ DRIFTS measurement and theoretical calculation are performed to unveil the reaction intermediates and the underlying toluene oxidation mechanism. The GQDs@BiOCl heterojunction could facilitate the adsorption and conversion of toluene and the reaction intermediates. Especially, the heterojunction greatly enhances the activation and conversion of benzoic acid and thus expedites the complete toluene degradation. This work presents a new insight on the design of high-performance photocatalysts for efficient degradation of typical air pollutants. [Display omitted] •The heterojunction of GQDs@BiOCl ultrathin nanosheet was synthesized.•The introduction of GQDs could enhance carrier separation and transportation.•Selective benzoic acid activation was enhanced on GQDs@BiOCl heterojunctions.•Toluene oxidation with high efficiency and excellent stability was achieved.•Mechanistic insights on the activation and degradation of toluene have been provided.