Surfactant-free synthesis uniform Ti1-xSnxO2 nanocrystal colloids and their photocatalytic performance

The preparation of Ti1-xSnxO2 nanocrystal colloids from peroxo-metal precursor by hydrothermal method was reported in this work. The obtained materials were investigated by means of XRD, Raman, TEM, XPS, ICP-AES, N-2 adsorption-desorption measurements (BET), PL and UV-vis spectroscopies technology. Photocatalytic degradation of phenol was studied under UV illumination. The results indicated that Ti1-xSnxO2 nanocrystal colloids were obtained in the nanometer scale (less than 10 nm) and the crystallite size was smaller than pure TiO2. Anatase phase, mixture phase (anatase and rutile) and rutile phase of Sn-doped TiO2 samples were formed, when x<0.04, 0.04<x<0.06 and x >= 0.06, respectively. The Sn4+ dopants presented substitution Ti4+ into the lattice of TiO2 alongside increasing the surface oxygen vacancies and the surface hydroxyl groups. Regarding photocatalytic activity, Sn-doped TiO2 samples (TiSn3) were nearly four times higher than undoped samples. This obvious beneficial effect could be attributed to high surface area, optimal crystalline phase and surface state modifications. (C) 2010 Elsevier B.V. All rights reserved.