Optimization of preparation conditions of Bi-doped TiO2/montmorillonite composites and its photodegradation of Rhodamine B

Abstract

In order to improve the photocatalytic degradation performance of titanium intercalated montmorillonite composites, the sol-gel method was used to intercalate bismuth/titanium polymerized hydroxyl cations into the interlayer of sodium-based montmorillonite (Na-MMT). The optimum synthesis conditions of Bi-doped TiO2/montmorillonite composite photocatalytic material (Bi/Ti-MMT) were investigated. Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and UV–vis diffusion reflectance spectrum (UV-Vis DRS) had been used to study the formation of Bi/Ti-MMT. Under the conditions of Bi/Ti molar ratio of 7 %, montmorillonite suspension mass fraction of 2 %, calcination temperature of 600 ℃ and calcination time of 3 h, the Bi/Ti-MMT had the highest photocatalytic activity, the degradation rate of Rhodamine B (RhB) was 88.16 %. In Bi/Ti-MMT composites, TiO2 existed in anatase phase. Bi3+ replaced Ti4+ and was doped into the TiO2 lattice, which can inhibit the growth of TiO2 crystals and reduce the band gap. The photoresponse range of the composite material was broadened to visible light, which improved the utilization of light.