CQDs modulating Z-scheme g-C3N4/BiOBr heterostructure for photocatalytic removing RhB, BPA and TC and E. coli by LED light

Abstract To improve the photocatalytic performance, it is necessary to reduce the combination of photo-induced charges and improve the absorbance intensity of visible light. Herein, we have reported novel heterojunctions of indirect Z-scheme CQDS/g-C3N4/BiOBr composites (noted as CN@BOB-CQDs). Various techniques proved the successful preparation of heterojunction structure between CQDs, g-C3N4 and BiOBr. Compared with g-C3N4 and BiOBr, the composites presented excellent performance in removing Rhodamine B (RhB), bisphenol A (BPA) and tetracycline (TC) and E. coli by LED light illumination. The improvement of photocatalytic properties was assigned to its good separation efficiency of generated charges and strong redox ability of its photo-excited electrons (e) and holes (h+), which realized from the Z-type photo-excited charges transition in CN@BOB-CQDs composite. Besides, CQDs could promote the transmission of electrons and enhance the absorbance intensity of visible light. Finally based on the radicals’ trapping experiments and the semiconductor energy band position, the photocatalytic mechanism on the degradation of RhB was illustrated.