Gas-Sensing Properties of Needle-Shaped Ni-Doped SnO2 Nanocrystals Prepared by a Simple Sol-Gel Chemical Precipitation Method

The preparation of needle-shaped SnO2 nanocrystals doped with different concentration of nickel by a simple sol-gel chemical precipitation method is demonstrated. By varying the Ni-dopant concentration from 0 to 5 wt %, the phase purity and morphology of the SnO2 nanocrystals are significantly changed. Powder XRD results reveal that the SnO2 doped with a nickel concentration of up to 1 wt % shows a single crystalline tetragonal rutile phase, whereas a slight change in the crystallite structure is observed for samples with nickel above 1 wt %. High resolution scanning electron microscopy (HRSEM) results reveal the change in morphology of the materials from spherical, for SnO2, to very fine needle-like nanocrystals, for Ni-doped SnO2, annealed at different temperatures. The gas sensing properties of the SnO2 nanocrystals are significantly enhanced after the nickel doping.