Sensitization of TiO2/SnO2 nanocomposites for gas detection

TiO2/SnO2 nanocomposites prepared by mechanical mixing of nanopowders are proposed as potential candidates for hydrogen sensing. Full compositional range from 100 mol % TiO2 to 100 mol % SnO2 has been covered and characterized by X-ray diffraction, XRD; Scanning Electron Microscopy, SEM; Transmission Electron Microscopy, TEM; Brunauer-Emmett-Teller, BET adsorption isotherms and impedance spectroscopy, IS. High and reproducible responses in reaction with hydrogen at a relatively low temperature have been obtained. Significant influence of humidity on the impedance spectra has been observed. Nanocomposite of 50 mol % TiO2/50 mol % SnO2 shows the highest response in interaction with hydrogen over the entire range of operating temperatures from 225 degrees C to 400 degrees C. Sensitization of TiO2/SnO2 is due to the formation of contact potential at grain boundaries that results in the charge transfer from SnO2 to TiO2 and facilitates oxygen adsorption. (C) 2013 Elsevier B.V. All rights reserved.