Synthesis of ZnO nanorods by spray pyrolysis for H2S gas sensor

Abstract

Hexagonal pillar shaped ZnO nanorods with different sizes have been successfully synthesized by spray pyrolysis technique (SPT). The equal amount of methanol and water is used as a solvent to dissolve the AR grade Zinc acetate for precursor solution. This solution is sprayed on to the glass substrate heated at 350°C. The films were characterized by ultra-violet spectroscopy (UV), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The deposition of thin films results in a layer comprising well-shaped hexagonal ZnO nanorods with diameter of 90–120nm and length of up to 200nm. The gas sensing properties of these films have been investigated for various interfering gases such as CO2, CO, ethanol, NH3 and H2S, etc. at operating temperature from 30° (room temperature) to 450°C. The results indicate that the ZnO nanorods thin films showed much better sensitivity and stability than the conventional materials to H2S gas (100ppm) at 50°C. The hexagonal pillar shaped ZnO nanorods can improve the sensitivity and selectivity of the sensors.