Ni Doped ZnO Nanostructures: Synthesis, Characterization and It's Sensing Behaviour at Lower Concentration and High Temperature

In this paper, hexagonal morphed ring structures of pure ZnO and Ni-doped ZnO nanomaterials were synthesized using zinc and nickel chlorides by sol-gel method. The phase conformation (hexagonal structure) of the synthesized nanomaterials was confirmed by X-ray diffraction (XRD) technique, followed by the composition was confirmed through Energy-dispersive X-ray (EDX) analysis. However, the shape and size of the synthesized nanomaterial was achieved through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM micrographs are recognized for the evidence of metamorphic behavior by ZnO, having hexagonal, disk shape and morphed to broccoli like surface. The crystallite size was reduced from 30 nm (pure ZnO) to 19 nm (Ni-doped ZnO). Thermal stability of the synthesized nanomaterials was studied through differential scanning calorimetry (DSC). The optical band gap variation was ascribed to the blue shift of 3.30 eV to 3.64 eV by doping due to reduction of crystallite size. An unsaturated volatile organic gas (VOC) C 2 H 2 sensing activity was tested for low ppm of 7–17 ppm at 110 °C and these values are compared with the earlier literature reported of various transition metal doped and un-doped ZnO nanostructures. The enhanced sensitivity of acetylene gas sensing was 600% for Ni-doped ZnO, which was 6.5 times higher than that of pure ZnO, response and recovery times are 124 and 281 s achieved by 0.03 mol of Ni doped ZnO at110 °C of 13 ppm. In conclusion the Ni-doped ZnO could be suitable materials for gas sensing applications.