(Ti,Sn)O₂ Mixed Oxides Nanoparticles Obtained by the Sol−Gel Route

Abstract

This paper focuses on the preparation and characterization of a titanium−tin mixed oxide (Ti,Sn)O2 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)O2 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)O2 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)O2 xerogels.