Highly sensitive H2S gas sensors based on CuO-coated ZnSnO3 nanorods synthesized by thermal evaporation

Abstract ZnSnO 3 one-dimensional (1D) nanostrutures were synthesized by thermal evaporation. The morphology, crystal structure and sensing properties of the CuO-coated ZnSnO 3 nanostructures to H 2 S gas at 100 °C were examined. Transmission electron microscopy and X-ray diffraction revealed both the ZnSnO 3 nanorods and CuO nanoparticles to be single crystals. The diameters of the CuO nanoparticles on the nanorods ranged from a few to a few tens of nanometers. The gas sensors fabricated from multiple networked CuO-coated ZnSnO 3 nanorods exhibited enhanced electrical responses to H 2 S gas compared to the uncoated ZnSnO 3 nanorod sensors, showing 61.7-, 49.9-, and 31.3-fold improvement at H 2 S concentrations of 25, 50, and 100 ppm, respectively. The response time of the nanorod sensor to H 2 S gas was reduced by the CuO coating but the recovery time was similar. The mechanism for the enhanced H 2 S gas sensing properties of ZnSnO 3 nanorods by the CuO coating is discussed.