Hydrothermal synthesis of ZnO nanoflakes composed of fine nanoparticles for H2S gas sensing application

The ZnO has the potential to form a number of nanostructures with various morphologies that can influence the gas sensing properties. Herein, hydrogen sulphide (H 2 S) gas sensing properties of the ZnO powder with novel 2D nanoflake morphologies prepared using a hydrothermal technique is reported. The physicochemical properties of the ZnO were investigated by XRD, FESEM, TEM, EDS, elemental mapping, XPS, Raman, and UV–Visible spectroscopy. The ZnO powders were utilized to fabricate the gas sensors, and the sensor's responses were tested at various operating temperatures and gas concentrations. The sensor exhibited a high response towards H 2 S gas in the range of 10–100 ppm at 250 °C and the highest response of 94% for 100 ppm H 2 S gas concentration. The transient resistance response of the ZnO sensor was tested for 100–10 ppm H 2 S gas concentration. The sensor showed the excellent repeatability of the resistance response. The H 2 S sensing mechanism and stability of the ZnO sensor were studied.