Synthesis of Z-scheme (001)-TiO2/Bi5O7I heterojunctions with enhanced interfacial charge separation and photocatalytic degradation of Rhodamine B.

A Z-scheme heterojunction was constructed by loading (001)-faceted TiO₂ onto Bi₅O₇I through a simple deposition method. Characterization of the obtained photocatalysts included SEM, TEM, XRD, FT-IR, XPS, UV–vis DRS, and PL. The results showed that (001)-TiO₂ nanosheets had been successfully anchored to the Bi₅O₇I nanobelts and the heterojunctions had been formed between them. The catalytic ability of the samples was assessed by degradation of Rhodamine B (RhB). The sample TB-20 exhibited the greatest apparent rate (0.04315 min⁻¹), which was about 3 times that of pure Bi₅O₇I. The enhanced photocatalytic activity can be attributed to the visible response and charge division of the (001)-TiO₂/Bi₅O₇I composite. The recyclability of the catalyst also showed good stability after four cycles with 90% degradation efficiency. Moreover, the degradation of RhB follows pseudo-first-order kinetics by non-linear least squares fitting to the degradation data. A plausible photocatalytic reaction mechanism has also been presented. [ABSTRACT FROM AUTHOR]