The effect of Ni doping concentration on the gas sensing properties of Ni doped SnO 2

The Ni doped SnO2 has been prepared by two-step hydrothermal treatment and calcination, and characterized by XRD, TEM and Brunauer Emmett Teller N2 adsorption–desorption analysis. The results exhibit the Ni doped SnO2 is heterostructure composed of Ni-SnO2 on the surface of SnO2 nanoparticles, which are polycrystalline tetragonal with high specific surface area and average grain size of about 10 nm. The sensors based on Ni doped SnO2 show very good gas sensing properties at low working temperature. The gas sensing properties of the Ni doped SnO2 are improved with low Ni-doping concentration (2–4 mol%), but further increase of Ni-doping concentration results in deteriorated response by low conductivity. The sensor based on 2 mol% Ni doped SnO2 and the sensor based on 4 mol% Ni doped SnO2 show ultrahigh responses to n-butanol and formaldehyde, respectively, with good selectivity. These sensors could be promising candidates for selective detection of n-butanol and formaldehyde.