Durability of Supported CoO{sub}x Nanoparticles for Low-Temperature CO Oxidation

摘要

On-stream durability of TiO{sub}2-supported CoO{sub}x catalysts, which had been prepared via incipient wetness technique, in the oxidation of CO has been inquired as a function of reaction parameters, such as CoO{sub}x contents, O{sub}2 and CO concentrations and reaction temperatures, and samples deactivated under such different conditions have been characterized using XRD, XPS, Raman and BET area measurements, and the analysis of elemental carbon deposited on the surface. The stability of CoO{sub}x/TiO{sub}2 during the course of CO oxidation reaction at 100°C had primarily a strong dependence on CoO{sub}x loadings; a sample of a 5 wt% CoO{sub}x/TiO{sub}2 catalyst gave a 100-% CO conversion up to 5 h after which the activity decreased with time and reached to conversions near 10%, while very rapid deactivation with 1 wt% CoO{sub}x occurred with 10 min. Repeated calcinations and measurements on a single sample of the 5 wt% CoO{sub}x catalyst altered the duration in the oxidation reaction. Other variables also caused distinctive behavior in the oxidation reaction. Characterization of the 5 wt% CoO{sub}x catalysts subjected to different reaction conditions suggests that surface reconstruction and carbonaceous materials deposition all may be associated with such duration impairment.