Synthesis of cadmium-doped zinc oxide nanoparticles via sol–gel method for ethanol gas sensing application

Pristine- and Cadmium-doped Zinc Oxide nanoparticles ( Zn 1 - x Cd x O) with 1-wt% and 3-wt% Cadmium concentrations have been synthesized via the sol–gel technique. The XRD results confirmed that the prepared nanomaterials possessed a Hexagonal Wurtzite crystalline structure. The mean crystalline size of the nanoparticles was estimated to be between 19 and 21 nm. The FESEM analysis confirmed that the prepared nanoparticles have irregularly shaped morphology. EDX study confirms the presence of Cadmium doping in ZnO. The fundamental vibrational bands of zinc oxide were confirmed by Raman spectra. The existence of various bonds had been confirmed using Fourier Transform Infrared spectroscopy (FTIR). The variation in electrical current with a variation in environment (air to Ethanol and then back to air) has been employed to determine sensing response at 100 ppm and 200 ppm concentrations of Ethanol. The percentage sensing response of the prepared materials has been observed to be increased with the rise in Cd content as well as Ethanol ppm level. The Cadmium-doped ZnO nanoparticles with 3 wt% of Cd have revealed the highest percentage sensing response of 24.82 and 30.92% at 100 and 200 ppm, respectively, which is greater than that of pristine ZnO. The lowest response time of 125 s was obtained for 3% Cadmium-doped ZnO nanoparticles. Thus Cadmium doping has improved the sensing response of pure zinc oxide nanoparticles.