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 degrees 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.