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Abstract: In this paper, the structural and gas sensing properties of nanocrystalline La0.7Pb0.3Fe0.4Ni0.6O3 was prepared by a sol–gel citrate method. The structural characteristics of the material were studied by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD pattern shows a nanocrystalline solid solution of La0.7Pb0.3Fe0.4Ni0.6O3 with a perovskite phase. The gas sensing properties were studied for different reducing gases such as H2S, ethanol, CO and LPG. The La0.7Pb0.3Fe0.4Ni0.6O3 powder showed large response to H2S gas at an operating temperature 250°C. Further improvement in response was achieved by the addition of 0.5wt% Pd to La0.7Pb0.3Fe0.4Ni0.6O3. The sensor showed a good response to 150ppm H2S gas at an operating temperature 200°C. [Copyright &y& Elsevier]

Abstract: The thick-film semiconductor sensor for liquid petroleum gas (LPG) detection was fabricated using a mixed WO3-based sensor. We present the characterization of both their structural properties by means of XRD measurements and the electrical characteristics by using gas-sensing properties. The sensing characteristics such as sensitivity, working range, cross-sensitivity and response time were studied by using nanosized WO3-based mixed with different metal oxides (SnO2, TiO2 and In2O3) and doped with noble metals (Au, Pd and Pt). The WO3-based mixed with 5wt.% In2O3 and 0.5wt.% Pd showed the higher sensing characteristic at low concentration of LPG sensor at an operating temperature 225°C. [Copyright &y& Elsevier]