Comparative study of the photocatalytic degradation of tetracycline under visible light irradiation using Bi24O31Br11-anchored carbonaceous and silicates catalyst support

Abstract This study compared two hydrothermally synthesized heterojunctions composites, Bi24O31Br10 – carbonaceous (activated carbon from zinc chloride [ACZ], phosphoric acid [ACH], carbonized material [CM]), and Bi24O31Br10 – silicates (SBA-15 and MCM-41), with nanosheets structure. The photocatalytic degradation of tetracycline (TC) was used to evaluate the synergistic influence of the catalyst supports for the corresponding heterojunction composites. The X-Ray diffractometry (XRD), Fourier transform infrared spectroscopy and scanning electron microscopy (SEM) confirmed the synthesis of the Bi24O31Br10 (BOB) – composites. After 120 min of visible LED light photocatalytic reactions, the degradation trend in removal efficiency of TC was BOB-ACZ > BOB > ACH > BOB-CM > BOB-MCM-41 > BOB-SBA-15 > BOB. The study reveals that Bi24O31Br11 – carbonaceous composite exhibits much better degradation efficiency than Bi24O31Br11 – silicates. Crucially, the synergistic surface interaction of ACZ with BOB, and the efficient separation of photogenerated charge carriers, from the SEM, XRD analysis, and photocurrent response, confirmed the photocatalytic enhancement of the heterojunction formation of the BOB-ACZ composite. This study further provides convincing insights on the superiority of carbonaceous nanomaterial to silica materials as efficient catalyst support in catalytic applications.