NO2 GAS SENSING PROPERTIES OF RHOMBUS-SHAPED ZnO NANORODS SYNTHESIZED VIA A SIMPLE HYDROTHERMAL METHOD

Abstract

In this study, rhombus-shaped ZnO nanorods were successfully synthesized via a simple hydrothermal method for potential application in toxic NO₂ gas sensing. The crystal structure and morphology of the material were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and Brunauer–Emmett–Teller (BET) surface area analysis, revealing a relatively large specific surface area of 8.67 m²/g. A gas sensor fabricated via a drop-coating technique using the synthesized material exhibited high sensitivity to NO₂ in the low concentration range of 0.1–2.0 ppm at an optimal operating temperature of 200 °C, along with excellent selectivity against interfering gases. Moreover, the sensor demonstrated good repeatability over eight consecutive switching cycles between NO₂ and dry air without significant degradation in response, indicating its strong potential for use in environmental NO₂ monitoring systems