Preparation and characterization of nanocomposites in system as: SnO2-xTiO2 (where x=25, 50 and 75 mol%)

Nanocomposite samples containing various molar compositions of tin and titanium oxides were synthesized by a sol-gel method using octadecylamine as controlling template agent. The structural and the crystalline features of the samples were investigated with Fourier Transformer Infra-red, X-ray diffraction, Transmission electron microscope (TEM) where the surface area was estimated by BET analysis. The crystalline parameters and the particle size were estimated by Rietveld quantitative phase analysis. It is interesting to mention that a reduction in the lattice parameters was detected upon introduction of various molar compositions of titanium oxide revealing that a part of titania is incorporated into the SnO2 lattice forming Ti1-xSnxO2 solid solution. The quantitative analysis claims that part of titanium oxide is incorporated substitutionally in the crystal lattice of SnO2, forming a solid solution and other parts are either segregated as separate rutile titania phase or dispersed as amorphous phase on the grain boundary of SnO2. The results show a remarkable reduction in particle size from 42 to 5 nm and increasing in the specific surface area up to 176 m(2)/g upon introduction of various content of titania implying the role of titania particles in preventing SnO2 crystallites from further growing up during the progress of calcination. TEM images show that pure tin oxide particles arranged in large aggregation in wormhole like structure, while the existence of titanium oxide are successfully creates spherical nanoparticles system organized in a definite structure. The optical absorbance spectra indicate a red shift and band gap narrowing upon introduction of titania which increase with increasing in titania contents.