A mechanochemical synthesis of nanostructured zinc oxide via acetate route for LPG sensing

Abstract

This article reports the liquefied petroleum gas (LPG) sensing of nanostructured zinc oxide (ZnO) synthesised via zinc acetate [Zn(CH3COO)2·2H2O] as precursor. The structural and morphological characterisations of the material were analysed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Structural analysis showed that material was highly crystalline having minimum crystallite size 15 nm. Surface morphological studies show nanospheres of ZnO throughout the surface, however not distributed uniformly. Optical characterisation of the sensing material was carried out by UV-Visible spectroscopy and FTIR spectroscopy. By Tauc plot, the estimated value of band gap of film was found 3.45 eV. The LPG-sensing properties of the ZnO pellet were investigated at room temperature for different vol.% of LPG. The variations in electrical resistance of the sensing pellet were measured with the exposure of LPG as a function of time. The maximum values of average sensitivity and sensor response factors were found ∼5 and 396, respectively, for 5 vol.% of LPG. The activation energy calculated from Arrhenius plot was found 0.61 eV. The response and recovery time of sensing pellet were found ∼90 and 110 s, respectively. These experimental results show that nanostructured ZnO is a promising material as LPG sensor.