Sensing Properties of Nanostructured Sm_1-xBa_xCoO₃ (x = 0, 0.1) obtained by Solution Method

Abstract

Some cobaltites with perovskite-type structure exhibit outstanding transport properties and high chemical activity, which make these materials suitable for applications in areas of gas sensors, heterogeneous catalysis, gas separation membranes and cathodes for solid oxide fuel cells. In this work, polycrystalline samples of Sm1-xBaxCoO3 (x = 0, 0.1) were prepared by an aqueous solution method using the corresponding nitrates. X-ray diffraction patterns of calcined samples showed that single-phase SmCoO3 was obtained at 900°C, whereas Sm0.9Ba0.1CoO3 was formed at 700°C. Electron microscopy images revealed that micron-sized particles were obtained for SmCoO3, whereas a nanostructured and nanoporous material wasobserved for Sm0.9Ba0.1CoO3. Electrical measurements made on thick films of the oxides revealed a semiconductor behavior in both phases, however Sm0.9Ba0.1CoO3 samples showed a larger conductivity compared with SmCoO3; dynamic response of resistance experiments made in air and CO2 revealed that Sm0.9Ba0.1CoO3 is selective to CO2.