Prominent ethylene glycol sensing of sol-gel derived ZnO and ZnO:Cu nano-structures

Abstract

Within this work, pristine zinc oxide and copper-doped powders were prepared using a sol–gel technic. Important physical properties such as morphological, optical, and structural features of the samples have been studied. Different data including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer–Emmett–Teller analysis (BET), UV–Vis spectrophotometry, and Fourier transform infrared spectroscopy (FTIR) were collected to investigate the physical features of the samples. In addition, the ethylene glycol vapor sensing capability of the prepared samples was investigated and compared with other vapors like as ethanol, methanol, acetone, isopropanol, and dimethylformamide. The results demonstrated that the samples have a very good selectivity to ethylene glycol (up to 50 times for ZnO and 13 times for ZnO:Cu 20%). The most important parameter of sensing namely operating temperature, real-time variation, sensitivity, and response/recovery times were also evaluated for pristine zinc oxide and copper-doped nano-structures. Specifically, the ZnO nano-structure sensor represented prominent sensitivity of about 37 and 139 towards for ethylene glycol concentration of 200 and 700 ppm, respectively.