Acetone sensors based on TiO2 nanocrystals modified with tungsten oxide species

Abstract

TiO2 nanocrystals were prepared by solegel/solvothermal processing and modified by the addition of W precursor before the solvothermal step. The W: Ti nominal atomic ratio (R-W) was fixed to 0.16 and 0.64. Surface modification of TiO2 occurred for R-W = 0.16 while for R-W = 0.64 nanocomposites with WO3 nanocrystals were obtained after heat-treatment at 500 degrees C. Pure TiO2 proved to be very poorly performing in acetone sensing in all the operating conditions. Instead, the addition of bothWconcentrations largely enhanced the sensor response. It ranged over two orders of magnitude of conductance variation for all the tested concentrations at as low as 200 degrees C operating temperature. The results showed that it is possible to enhance the performance of an otherwise almost inactive oxide like TiO2 by proper combination with another more active oxide like WO3. (C) 2016 Elsevier B.V. All rights reserved.