TiO2–SnO2 nanomaterials for gas sensing and photocatalysis

Nanopowders of TiO2–SnO2 over a full composition range extending from 100 mol% TiO2 to 100 mol% SnO2 are obtained by the sol–gel method from TTIP and SnCl2·5H2O precursors of Ti and Sn, respectively followed by calcination at 400 °C. The samples are characterized by means of BET, XRD and TEM. Optical properties of the prepared nanomaterials are studied as well. TEM images indicate that the nanoparticles are regular in shape. The specific surface area, SSA of TiO2 is 95 m2/g while that of SnO2 amounts to 129 m2/g. The highest SSA of 156 m2/g is achieved at 20 mol% of TiO2. Occurrence of rutile, anatase and brookite polymorphic forms depends on the chemical composition of nanopowders. Formation of rutile-type solid solution of TiO2–SnO2 over the range of 0–80 mol% TiO2 is confirmed by Vegard rule applied to lattice constants. Electronic band gap decreases with Ti content from 3.84 eV (100 mol% SnO2) to 3.18 eV (100 mol% TiO2).