Structural, photocatalytic, biological and catalytic properties of SnO2/TiO2 nanoparticles

TiO2 and SnO2/TiO2 nanoparticles with different SnO2 contents (0-20 wt%) were synthesized via surfactant assisted sol-gel method using a cationic surfactant (cetyltrimethylammonium bromide, CTAB). The effects of SnO2 content on the structural, optical, and catalytic activity of TiO2 have been studied by X-ray diffraction (XRD), Transmission electron microscope (TEM), Scanning electron microscope (SEM), Fourier transformer infrared (FTIR) and UV vis diffuse reflection spectroscopy (DRS). The total surface acidity of the prepared samples was measured by nonaqueous titration of n-butylamine in acetonitrile and the types of Bronsted and Lewis acid sites were distinguish using FTIR spectra of chemisorbed pyridine. XRD patterns analysis indicates that the crystallite size reduced remarkably and the transformation of anatase-to-rutile phase accelerated greatly with increasing the SnO2 content. TEM images exhibit a spherical shape with an average particle size varying in the range 10-24 nm and high -resolution TEM images (HRTEM) show lattice fringes with interplanar spacing 0.35 nm and 0.32 nm which corresponding to anatase and rutile phases, respectively. SEM images show the amount of SnO2 on the TiO2 surface increases with increasing the SnO2 content and the particles of SnO2 were aggregated on TiO2 surface with increasing SnO2 content to 20% wt. The catalytic activity was tested by various applications: Photodegradation of Methylene Blue (MB) and Rhodamine B (RhB) under UV vis irradiations and synthesis of xanthene (14-phenyl-14H-dibenzo [a,j] xanthene). Antibacterial and antioxidant activities were also studied. The antibacterial property test was carried out via agar disc diffusion method, and the results indicated that the prepared catalysts showed moderate antibacterial activity.