CO sensing characteristics of hexagonal-shaped CdO nanostructures prepared by microwave irradiation

CdO hexagonal sheets were prepared by a simple chemical route assisted by microwave irradiation. Two different preparation procedures were adopted and characterized in the presence of urea as a directing agent and poly-vinyl-pyrrolidone (PVP) as a surfactant. The morphological and microstructural characteristics were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) analysis, diffuse reflectance infrared spectroscopy (DRIFT) and X-ray powder diffraction (XRD). Characterization results have demonstrated that, after annealing at 300 degrees C, the formation of CdO hexagonal sheets with different thickness. Thicker sheets were obtained when urea and PVP were used. Chemoresistive devices consisting of a thick layer of CdO hexagonal sheets on interdigitated alumina substrates had been fabricated and their electrical and sensing characteristics were investigated. The sensor performances of the CdO sheets for carbon monoxide were reported. The results indicated that both the sensors exhibited high response and quick response-recovery dynamics. The sensing properties were explained in terms of rapid gas diffusion onto the sensing layer surface. (C) 2012 Elsevier B.V. All rights reserved.