Preparation, structural and photocatalytic activity of Sn/Fe co-doped TiO2 nanoparticles by sol-gel method

Pure and Sn/Fe co-doped (0.2 at.% Sn and 0.6 at.% Fe, 0.6 at.% Sn and 0.2 at.% Fe, 1.0 at.% Sn and 1.0 at.% Fe) TiO2 nanoparticles were synthesized via a sol-gel method and subsequently calcined at different temperatures. Furthermore, the particles were analyzed by TG-DSC, XRD, TEM, HRTEM, EDS, SAED and UV-Vis for investigating the influences of dopant and calcination temperature on the thermal effect, composition, morphology, energy band gap (E-g) and the degradation efficiency of methyl orange (MO) under various light irradiations respectively. Results indicated that Sn/Fe co-doping inhibited the crystallization transformation from anatase to rutile phase of TiO2 and decreased the E-g. The increased calcination temperature and Sn/Fe co-doped effect brought about the abnormal grain growth of TiO2 nanoparticles. 0.6 at.% Sn/0.2 at.% Fe and 1.0 at.% Sn/1.0 at. % Fe co-doped TiO2 nanoparticles presented better photocatalytic performance than pure and 0.2 at.% Sn/0.6 at. % Fe co-doped TiO2 nanoparticles under visible light irradiation mainly due to the decreased E-g. On the contrary, 0.2 at.% Sn and 0.6 at.% Fe co-doped TiO2 nanoparticles calcined at 650 degrees C showed the most excellent photo catalytic performance under UV light irradiation, which was about twice as large as that of pure TiO2 possibly due to the formed hybrid structure of anatase and rutile phase as well as the h(+)-mediated decomposition pathway.