Photocatalytic decolorization of Rhodamine B dye using novel mesoporous SnO2–TiO2 nano mixed oxides prepared by sol–gel method

Abstract

Abstract The photocatalytic removal of Rhodamine B dye was successfully carried under UV irradiation over mesoporous SnO2/TiO2 nanoparticles embedded various molar compositions of SnO2 (0–25%) synthesized by sol–gel process using polymethylmethacrylate as template. Structural and textural features of the samples were investigated by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherm, Fourier transformer infra-red (FTIR) and transmission electron microscope (TEM). The existence of tin oxide is associated with remarkable reduction in particle size to 6 nm and increasing the surface area up to161 m2/g revealing the successful role of SnO2 in manipulating high surface area nanoparticles. The TEM results revealed that well-dispersed and uniform spherical nanoparticles with diameters of 6 nm were embedded in the sample matrix. Both adsorption and UV irradiation are contribute for decolorization of about 92% of Rhodamine dye over the sample embedded 10% SnO2 after 3 h of the reaction compared with 70% only decomposition over pure titania. The photocatalytic decolorization of the dye follows a pseudo-first-order kinetics and the apparent rate constant was increase with increasing the tin oxide content up to 10%. The existence of tin oxide is associated with remarkable reduction in particle size, increasing the oxidizing power and increasing the efficiency of charge carrier separation which considered the main reasons for a remarkable increasing in the catalytic activity of the samples. As the mode of preparation is economically feasible, we can consider this catalyst to be very effective to decolorize various organic dyes.