Development of CdS-doped TiO2 nanocomposite as acetone gas sensor

Abstract

In recent years, much interest has been shifted towards the design and development of gas sensing devices for use of detecting and identifying toxic gases. In this work, a CdS doped TiO2 nanocomposite, with 1–2 wt % CdS, is prepared in the form of films as a gas sensor. The results are described with X-ray diffraction (XRD) and atomic force microscopic (AFM) images. The response of the fabricated sensor is measured with exposure to acetone, propanol, and LPG of varied concentrations (0–5000 ppm) in ambient air at room temperature. It is found that an optimized 2 wt% CdS-doping extends the highest response, i.e. 71% for 5000 ppm acetone, which is more selective over propanol or LPG, and also superior than reported ever for TiO2 based sensors. The response and recovery times are improved from 85 s to 190 s for undoped TiO2 sensor to 55 s–115 s for acetone (5000 ppm). Possible mechanisms of finely tuned sensing properties are described in light of the microstructure.