(Ti,Sn)O2 mixed oxides nanoparticles obtained by the sol-gel route

This paper focuses on the preparation and characterization of a titanium-tin mixed oxide (Ti,Sn)O-2 with anatase structure. The preparation method is based on a sol-gel technique using titanium tetra-isopropoxide and tin tetrachloride as precursors. The obtained TiO2 and titanium-tin mixed oxide xerogels and their heat-treated products were characterized by thermal analysis, X-ray diffractometry, Raman spectroscopy, and X-ray absorption spectroscopy. The results indicate that the (Ti,Sn)O-2 was obtained in the nanometer scale and the crystallite size was smaller than the pure TiO2 obtained by a similar route. The mixed oxide was obtained as a solid solution. Compared to the bulk TiO2, the Raman spectra of both TiO2 and (Ti,Sn)O-2 xerogels present an excessive Eg peak broadening, which was attributed to the presence of surface low-coordinated titanium atoms. The occurrence of these species was confirmed by XANES and EXAFS spectra of both pure TiO2 and (Ti,Sn)O-2 xerogels.