Synthesis of nanocrystalline La-Pb-Fe-O perovskite and methanol-sensing characteristics

The nanocrystalline La0.8Pb0.2FeO3 powder was prepared by novel sol-gel self-combustion method using polyvinyl alcohol. The nanosized powders were obtained by quick combustion. From the obtained powder, pressed samples were executed in shape of disks, heat treated for 40 mm at 900 degrees C. The samples were investigated with regard to their composition and microstructure, using XRD and SEM-EDX methods, and their electric properties and response to four test gases. The compound exhibits the orthorhombic symmetry (space group Pnma) and crystallizes in the perovskite-like cell of LaFeO3, a porous granular and uniform structure with average grain size of 250 nm and an effective porosity of 31%. The La0.8Pb0.2FeO3 sensors show p-type semiconducting properties for all studied gases within the temperature range of 100-380 degrees C. The La0.8Pb0.2FeO3 sensors have the best response and selectivity to methanol gas. The highest response to methanol gas (400 ppm) is 146.6 at 230 degrees C. (C) 2011 Elsevier B.V. All rights reserved.