Paper SS-ThP19
Synthesis of Nanostructured CoSb2O6 by a Co-Precipitation Method and its Potential Application as a Gas Sensor Material

Thursday, October 23, 2008, 6:00 pm, Room Hall D

Nanostructured powders of CoSb2O6 possessing the trirutile-type structure, were synthesized by a co-precipitation method, using antimony chloride and cobalt nitrate. During this process a precipitate was obtained when the reagents were mixed in ethanol, which was stirred for 24 h. Microwave radiation at low power was applied for the evaporation which produced a solid precursor. The thermal decomposition of the precursor, from room temperature to 700ºC in air, was made in order to investigate the crystal structure evolution while increasing the calcination temperature. To perform this characterization X-ray powder diffraction was used, resulting that the tetragonal CoSb2O6, with cell parameters a = 4.6544 Å and c = 9.2823 Å, and space group P42/nmn, can be obtain from 600ºC. The observation of the calcined materials by SEM shows that the main microstructure produced corresponds to a filamentary shape, with a length between 100 to 600 nm. The observation by TEM of these filaments revealed that are composed by an arrangement of nanoparticles with an average size of 20 nm. To test CoSb2O6 as a gas sensor material, the powder calcined at 700 ºC was deposited on alumina substrates using the screen-printing method. DC electrical characterization was performed in air, O2 and CO2, from room temperature to 600oC. The dynamic response of resistance was studied by supplying alternatively the gases while recording the electrical resistance; which increased in approximately 1000 ohms when detecting CO2, whereas for O2 the change was in the order of 100 ohms.