Carbon dioxide gas sensing behavior of nanostructured GdCoO3 prepared by a solution-polymerization method

In this work, nanostructured GdCoO3 powders were prepared by an aqueous solution-polymerization method using cobalt and gadolinium nitrates, and a mixture of polyvinyl alcohol and polyvinyl pyrrolidone. By X-ray powder diffraction GdCoO3 was obtained at 650 degrees C in air. The microstructure of the powders calcined from 610 to 650 degrees C was analyzed by SEM and TEM: from these results, the typical morphology corresponds to nanostructured laminas. An increase in the inner porosity while increasing the calcination temperature was also observed. The gas sensing characterization was performed at 400 degrees C, revealing times of response of approximately 10 s in both oxygen and carbon dioxide. The resistance variations were 26 and 4 Omega, respectively. The ability of nanostructured GdCoO3 to detect changes in the concentration of O-2 and CO2 was studied. In CO2, unique curves were obtained for each gas concentration; however, the results registered in O-2 revealed a lower performance. (C) 2009 Elsevier B.V. All rights reserved.