H2S sensing properties of nanocrystalline Sr2FeO.6NiO.4MoO6 thick film prepared by sol–gel citrate method

Nanocrystalline Sr2FeMoO6 (SFMO) belonging to the group of double perovskite oxides, was prepared by the sol–gel citrate method. The structural and microstructural characterization has been carried out with the help of X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. XRD of Sr2Fe1−xNixMoO6 (SFNMO) shows the formation of solid solution with average grain size of about 40 nm. A comparative study of gas sensing behaviour of Sr2FeMoO6 and Sr2Fe1−xNixMoO6 with reducing gases like hydrogen sulfide (H2S), liquid petroleum gas (LPG), hydrogen (H2), ethanol (C2H5OH) and carbon monoxide (CO) were also discussed. The sensitivity is calculated by measuring the change the resistance of the sensor material in the presence of gas. Among the different composition of x (x = 0.2, 0.3, 0.4, 0.5), Sr2Fe0.6Ni0.4MoO6 (x = 0.4) shows better response to H2S gas at 260 °C. Incorporation of palladium (Pd) improves the gas response, selectivity, response time and reduced the operating temperature from 260 to 220 °C for H2S gas.