Mechanism of carbon monoxide oxidation on supported copper catalysts modified with cerium and platinum (original) (raw)
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Carbon monoxide oxidation over CuO/CeO2 catalysts
Catalysis Today, 2004
CuO/CeO 2 catalysts prepared by co-precipitation, deposition-precipitation and impregnation methods were extensively investigated for CO oxidation reaction. It was shown that the catalytic behaviors of CuO/CeO 2 catalysts greatly depended on the preparation routes, which caused significant differences in the redox properties and the dispersion of copper species. The remarkable redox ability of CuO/CeO 2 at lower temperatures was found to play an essential role in CO oxidation reaction. The catalysts prepared by co-precipitation exhibited the highest catalytic activity in CO oxidation with CO total conversion at 85 • C. The structural characters as well as the redox features of CuO/CeO 2 catalysts were comparatively investigated by XRD, TPR, cyclic voltammetry and XPS measurements. The discrepancies in the dispersion of copper species and the degree of interaction between copper species and ceria determined the reversible redox properties, and consequently the catalytic performance.
Applied Catalysis A: General, 2005
CeO 2 nano-crystals were synthesized by a sol-gel process and then used as support for CuO/CeO 2 (sol-gel) catalysts prepared via impregnation method. For comparison, the commercial CeO 2 was also used as a support for CuO/CeO 2 (commercial) catalysts prepared via the same method. The samples were characterized by means of BET, XRD, UV-vis, TPR and XPS. The catalytic properties of the CuO/CeO 2 catalysts for low-temperature CO oxidation were studied by using a microreactor-GC system. The prepared spherical CeO 2 nano-crystals have much smaller particle size, better crystallinity and larger surface area than the commercial CeO 2 . XPS analysis indicated the presence of reduced copper species in the CuO/CeO 2 catalysts. TPR showed that there are different copper species in the catalysts. The influence of calcination time, temperature and CuO loadings on the catalytic activity of CuO/CeO 2 catalysts has been studied. The CuO/CeO 2 (sol-gel) catalysts exhibited higher catalytic activity than the CuO/CeO 2 (commercial) catalysts. Compared with CuO/CeO 2 catalysts prepared via other techniques, our catalysts exhibited similar or even better catalytic performance. # Fig. 4. XRD patterns of CuO/CeO 2 catalysts with various CuO loadings: (a) CuO/CeO 2 (sol-gel); (b) CuO/CeO 2 (commercial).