Ultra-small cesium silver bismuth bromide quantum dots fabricated by modified hot-injection method for highly efficient degradation of contaminants in organic solvent

•Cs2AgBiBr6 quantum dots were synthesized from the hot injection with a diameter around 2.8 ± 1.0 nm.•97% of rhodamine B and 90% of methyl orange are degraded within 10 and 30 min by visible-light photocatalysis, respectively.•60% of tetracycline hydrochloride may be removed at 30 min by the visible-light photocatalysis, which is 7 times higher than that of P25.•The main active radicals for the photodegradation are superoxide radicals and holes. Lead-free halide perovskite material has drawn fast-growing interest due to its superior solar-conversion efficiency and nontoxic nature. In this work, we have successfully fabricated cesium silver bismuth bromide (Cs2AgBiBr6) quantum dots utilizing the hot injection method. The as-synthesized quantum dots were characterized by combined techniques, which showed remarkable visible-light photocatalytic activity for organic dyes and antibiotic degradation in ethanol. Specifically, about 97% of rhodamine B and methyl orange may be removed within 10 min and 30 min, respectively. Additionally, 60% of antibiotic residue of tetracycline hydrochloride is degraded in 30 min which is 7 times more than that on commercial titania (P25). The reactive species for the photodegradation are determined through capture experiments, and a reaction mechanism is proposed accordingly. This work provides a novel photocatalyst for the selective removal of diverse organic contaminants in ethanol and an alternative for the potential application of lead-free halide perovskites. The lead-free Cs2AgBiBr6 double perovskite quantum dots were successfully synthesized from the hot injection method and utilized for the degradation of refractory organic pollutants in ethanol solution, demonstrating superior photocatalytic performance. [Display omitted]