In the past years, conductometric gas sensors based on semiconducting metal oxides have been widely used and investigated in the detection of a variety of gas and vapors. Recently, the introduction of new semiconducting materials with perovskite structure allowed the development of new gas sensors with promising performances [1]. In this paper we focused our attention on NdFeO3 nanocrystals, as sensing material for detecting low concentration of acetone in air. First, the NdFeO3 sensing material was synthesized by a thermal treatment method [2] as follows: an aqueous solution of polyvinyl pyrrolidone (PVP) was prepared by dissolving the polymer in 100 ml of deionized water at 90 ˚C then metal nitrates with equal molar ratios were added to solution while the temperature of solution was kept at 90 ˚C for 2 hours. The mixed solution was placed in oven (100 ˚C) for 24h. The solid product formed was crushed, ground in a mortar to form a soft powder and finally annealed at 700˚C (in air for 3 h). XRD diffraction pattern of NdFeO3 nanocrystals (average particle size = 28 nm) is shown in Fig. 1.
