The hierarchical layered microsphere of BiOIxBr1-x solid solution decorated with N-doped CQDs with enhanced visible light photocatalytic oxidation pollutants

The hierarchical layered microspheres of BiOIxBr1-x solid solution decorated with N-CQDs were rapidly synthesized by one-step in-situ co-precipitation. Nitrogen doping caused carboxyl and amino groups on the surface of CQDs, These groups combined with Bi atoms in bismuth-derived precursors to provide in situ growth site for BiOIxBr1-x, thus achieved strong binding effect between BiOIxBr1-x and N-CQDs, which was beneficial to charge transfer. Meanwhile, BiOIxBr1-x hierarchical layered microspheres were assembled by nanosheets with a thickness of about 23 nm, which could generate multiple reflection of light, and thus enhanced the light-harvesting. Under visible light irradiation, N-CQDs/BiOI0.25Br0.75 presented the remarkable photocatalytic activity when the loading amount of N-CQDs was 1.25 wt%. The removal rate of phenol and tetracycline hydrochloride was 98.7% within 3 h and 96.6% after 5 min, respectively. The reason of improvement activity of N-CQDs/BiOIxBr1-x was due to the multiple scattering of light between hierarchical layered BiOxBr1-x as well as the internal electric field from N-CQD to BiOI0.25Br0.75.