Improvement of the gas sensing behavior in nanostructured Gd0.9Sr0.1CoO3 by addition of silver

Single-phase Gd0.9Sr0.1CoO3 perovskite was prepared by the solution-polymerization method from an aqueous solution containing a mixture of the corresponding metal nitrates, polyvinyl alcohol and sucrose. The calcination of precursor powders at 600 °C in air produced a crystalline nanostructured oxide possessing good connectivity between nanoparticles. The effect of addition of 4% weight of silver in Gd0.9Sr0.1CoO3 was characterized by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The average particle size of Gd0.9Sr0.1CoO3 and Gd0.9Sr0.1CoO3–Ag was 45 nm and 55 nm, respectively. Both materials exhibit a moderate sensitivity to carbon dioxide and oxygen; however, the addition of silver to Gd0.9Sr0.1CoO3 produced an increment in the resistance change of 40.7% in O2 and 47% in CO2.