Fabrication of SnSO4-modified TiO2 for enhance degradation performance of methyl orange (MO) and antibacterial activity

Abstract SnSO4-modified TiO2 nanoparticles containing different SnSO4 contents were prepared, and their morphology, light absorption properties and photocatalytic degradation and antibacterial activities were determined. The results revealed that the samples had mesoporous structures consisting of anatase phase, and their surface area increased with increasing SnSO4 content. The XPS analysis showed that Sn had the valence state of +4 and existed as SnO2; and S existed on the surface as sulfate. The photocatalytic degradation assay showed that SnSO4-modified TiO2 shifted the absorption peak of methyl orange (MO), and gradually changed its structure from azo structure to quinone structure. Compared with that of pure TiO2, SnSO4-modified TiO2 had higher MO degradation activity under ultraviolet irradiation and visible light irradiation and had higher antibacterial activity against Escherichia coli and Staphylococcus aureus under visible light and dark conditions. The experiments on MO degradation in the presence of scavengers also showed that O▪2- was the predominant radicals generated during degradation under visible light irradiation. The data also indicated that the SnSO4-modified TiO2 nanoparticles could produce reactive oxygen species (ROS) under visible light and dark conditions, and the produced ROS, especially for ▪OH radicals, significantly play roles in their antibacterial activity under visible light.