초록 |
A TiO2-supported CoOx catalyst with 5 wt% Co has been used for CO oxidation at low temperatures, such as 50 and 100°C, under a net oxidizing condition, and samples of the catalyst have been characterized using TPD, XPS and XRD measurements. The catalyst after calcination at 450°C gave highest activity for this CO oxidation, and XPS measurements yielded that a 780.2-eV Co 2p3/2 main peak appeared with this sample and this binding energy was similar to that measured with pure Co3O4. After calcination at 570°C, the catalyst, which had possessed practically no activity in the oxidation reaction, gave a Co 2p3/2 main structure peak at 781.3 eV which was very similar to those obtained for synthesized ConTiOn+2 compounds, and this catalyst sample had relatively negligible CO chemisorption as observed by TPD spectra. XRD peaks indicating only the formation of Co3O4 particles on titania surface were developed in the catalyst samples after calcination at temperatures ≥ 350°C. Based on these characterization results, five types of Co species could be modeled to exist with the catalyst calcined at different temperatures. |