Structural, electrical and ethanol sensing properties of double-doping LaFeO3 perovskite oxides

Nanosize La0.8Ca0.2-xPbxFeO3 (x=0.00, 0.05, 0.10, 0.15 and 0.20) compounds were prepared by the sol-gel method using the citric acid route. The Rietveld refinement, from the X-ray diffraction patterns, revealed that the sample with x=0.00 presents a single phase that crystallizes in the orthorhombic symmetry with a Pnma space group. However, we found that the substitution of calcium (Ca) ion by lead (Pb) one does not change the principal phase but generates the formation of Fe3O4 and Ca2Fe2O5 secondary phases. The electrical sensitivity of La0.8Ca0.2-xPbxFeO3 compounds to ethanol gas was investigated using broad band dielectric spectroscopy, at temperature up to 400 degrees C. This study demonstrated that the Pb-doping can lead to the resistivity modification and sensitivity improvement of the of La0.8Ca0.2FeO3 sample. Among the investigated compounds, the La0.8Ca0.1Pb0.1FeO3 (x=0.10) sample showed the highest sensitivity to ethanol. The electrical response was studied in function of the quantity of ethanol presented in the measurement setup. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.