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The physico-chemical properties of ceria (CeO2) and rare earth modified ceria (with La, Pr, Sm, Y) catalysts are studied and correlated with the soot oxidation activity with using O2 and O2 + NO. CeO2 modified with La and Pr shows superior soot oxidation activity with O2 compared with the unmodified catalyst. The improved soot oxidation activity of rare earth doped CeO2 catalysts can be correlated to the increased meso/micro pore volume and the stabilisation of the external surface area. On the other hand, unreducible ions decrease the intrinsic soot oxidation activity of rare earth modified ceria with both O2 and NO + O2 due to the decreased amount of redox surface sites. The catalyst bulk oxygen storage capacity is not a critical parameter in determining the soot oxidation activity. The modification with Pr shows the best soot oxidation with both O2 and O2 + NO compared with all other catalysts. [ABSTRACT FROM AUTHOR]

Carbon-coated monolithic catalysts were prepared by dipcoating a cordierite substrate in a Furan resin, after which the ruthenium was incorporated by impregnation with a [RuCl5]2- complex. Immobilization of the precursor proceeded particularly via weak physisorption. Since the carbon-coated monolithic supports have a broad pore-size distribution, redistribution of the ruthenium precursor occurred upon drying due to capillary forces, resulting in low dispersion. A significant amount of ruthenium is present on the surface of the carbon inclusions located deep in the cordierite walls, making the diffusion path of the reactants to the active ruthenium sites considerably larger than the average carbon-coating thickness. For successful application of the carbon-coated monolithic catalysts in gas–liquid reactions, the deposition of carbon in the walls of the monolith should be prevented and maldistribution of ruthenium upon drying should be solved. [ABSTRACT FROM AUTHOR]