Effect Synthesis Time of CeO₂ Nanoparticles by Microwave-Assisted Hydrothermal as a Sensing Device on CO Gas Sensitivity

The study presents CeO₂ particles synthesized by the microwave-assisted hydrothermal method using different synthesis times for the analysis of sensitivity to carbon monoxide gas, aiming at its application as a sensor material to prevent poisoning caused by this highly toxic gas. Structural, morphological and spectroscopic and electrical behaviors were analyzed by X-ray diffraction, Rietveld refinement, transmission electronic microscopy, Raman scattering spectroscopy, optoelectronic characterization chamber and FT-IR. The samples presented fluorite-type cubic structures, increase in crystallinity and particle size with the variation synthesis time from 5 to 8 minutes. From the micrographs it was observed that the nanoparticles initially were spherical with a surface domain (200), and the synthesis time made them cubic/polyhedral with a surface (111), showing differences in defects and influencing in its properties. The sample synthesized at 8 minutes showed the best result with response and recovery time of 16 and 2 seconds, respectively, at 390 °C, therefore promising for the fabrication of CO gas selective sensing device.

Keywords:
cerium dioxide; synthesis; microwave assisted hydrothermal method; carbon monoxide