Selective-detection NO at room temperature on porous ZnO nanostructure by solid-state synthesis method

High sensitivity and selectivity detection of NO at room temperature has always been full of challenges. In this work, a kind of porous ZnO with coralline-like nanostructure was prepared by a rapid and simple solid-state synthesis strategy, using zinc acetate and oxalic acid as precursors. Structural analysis and morphological investigations of the ZnO powder showed that it has a large specific surface area (32.75 m² g^-1) and many nanometer-sized channels between ZnO nanoparticles. This is beneficial to the adsorption and desorption of NO, which is an important reason for the selective detection of NO by the ZnO powder at room temperature. So based on the ZnO powder, a gas sensor was fabricated and its gas-sensing properties were investigated. It exhibited outstanding response (23.59) and fast response time (331 s) to 40 ppm of NO at room temperature (21 ± 2 °C). As the relative humidity study changed from 17% to 80% at 10 ppm of NO, the sensitivity of the sensor changed little, only decreased from 1.43 to 1.12. The stability study was also carried out. Under the concentration of 5 ppm of NO, the relative standard deviation was 0.33% within 8 days, which indicates that the obtained sensor is suitable for practical application.