High Performance CO Gas Sensor Based on ZnO Nanoparticles

Carbon monoxide sensor was fabricated using ZnO nanoparticles, synthesized by sol–gel technique, as sensing layer. The morphology and structure of the prepared nanopowder were analyzed using X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM). Photoluminescence (PL) measurements were carried to investigate the defects in ZnO. The sensing tests were performed by a homemade setup. XRD pattern indicate that the prepared ZnO nanopowder has a crystallite size average around 50 nm. TEM and SEM images reveal that the ZnO nanopowder is formed of agglomeration of spherical particles with a size of 50 nm which is in good agreement with XRD analysis. The prepared gas sensor exhibits a response of 74% towards 80 ppm of CO gas with a response/recovery times of 21 and 70 s, respectively at 250 °C and high stability with time. The good sensing properties of ZnO nanoparticles towards CO gas indicate their potential application for the fabrication of low power and highly selective sensors.