Photocatalytic activity tuning in a novel Ag2S/CQDs/CuBi2O4 composite: Synthesis and photocatalytic mechanism

CuBi2O4 dumbbell-like architecture built from nanorods was synthesized by a simple coprecipitation route. The growth process of the dumbbell-like architecture was investigated by varying the reaction duration time. Carbon quantum dots (CQDs) and Ag2S nanoparticles were assembled on the surface of the CuBi2O4 dumbbell-like architecture to produce CQDs/CuBi2O4 and Ag2S/CQDs/CuBi2O4 composites. Compared to bare CuBi2O4, the composites, particularly Ag2S/CQDs/CuBi2O4, manifest an increased visible light absorption, increased photocurrent density and decreased charge-transfer resistance. Using simulated sunlight as the light source and rhodamine B (RhB) dye as the target organic pollutant, the photocatalytic activity of the samples was investigated. It is demonstrated that the Ag2S/CQDs/CuBi2O4 composite exhibits the highest photocatalytic activity toward the RhB degradation. This is due to the highly efficient separation of electron/hole pairs and increased visible light absorption of the Ag2S/CQDs/CuBi2O4 composite.