(Ti, Sn)O2 binary solid solutions for gas sensing: Spectroscopic, optical and transport properties

Novel TixSn1−xO2 (0.3 < x < 0.9) nanostructured oxides for gas sensing, have been synthesized and characterized through a great variety of investigation techniques, such as electron microscopy, X-ray diffraction, specific surface area measurements, UV–vis and IR spectroscopies, photoluminescence emission spectra and finally electrical measurements. All structural investigations showed solid solutions of the two single oxides; only the oxide with x = 0.7 showed a beginning of spinodal decomposition revealed by XRD. Surprisingly, the samples with x = 0.3 and 0.5 exhibited carbon monoxide response much higher than for pure SnO2. Investigations on this point, performed through spectroscopic measurements in the presence of CO, suggest a different behaviour of the solid solutions from the single oxides.