Zeolite A coated Zn1-XCuXO MOS sensors for NO gas detection

In the current study, a novel and highly sensitive gas sensing material for the detection of NO gas was reported. Copper doped zinc oxide nanostructures (Zn1-xCuxO, where x = 0.25 steps) were grown as a semiconducting sensor material by using Successive Ionic Layer Adsorption and Reaction (SILAR) method. The structural, morphological and optical properties of nanostructures were investigated by X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and UV-visible spectrometer. NO gas sensing measurements were carried out as a function of temperature and gas concentrations. The sensors exhibited acceptable responses towards 50 ppb NO gas at operating temperature of 55 degrees C. The sensors were optimized and the maximum response of 8% was obtained for the Zn0.75Cu0.25O sensor. To increase sensor selectivity, zeolite A (LTA) microporous film, used as a filter, was coated on the optimized Zn0.75Cu0.25O sensor by using secondary growth method. zeolite A coated Zn0.75Cu0.25O sensor exhibited both high selectivity and high response towards NO gas. The detection limit of the zeolite coated Zn0.75Cu0.25O sensor was shifted to 20 ppb for NO gas at operating temperature of 25 degrees C.