Electrical and CO-sensing properties of SmFe0.7Co0.3O3 perovskite oxide

In this work, nanocrystalline powders of perovskite-type compounds SmFe1−xCoxO3 (x = 0, 0.3) were prepared by sol–gel method. The morphology, electrical and carbon monoxide (CO) sensing properties of the nanocrystalline powders were studied by X-ray diffraction technique, Scanning Electron Microscopy (SEM), and electrical resistance measurements from 40 to 400 °C. The optimal value of CO-sensing response (S = Rg/Ra, here Ra = resistances in atmospheric air with humidity = 45%, Rg = resistances in CO within the background of atmospheric air with humidity = 45%) for nanocrystalline SmFe0.7Co0.3O3-based sensor is about 8.43 at 150 °C as the CO concentration is equal to 500 ppm. In addition, the SmFe0.7Co0.3O3 sample shows a good selectivity to the gas CO.