Ceria-based catalytic coatings on biomorphic silicon carbide: A system for soot oxidation with enhanced properties

In order to be efficient, catalysts require an adequate substrate with tailored porosity, specific surface area and pore size distribution. This work reports on the use of biomorphic silicon carbide, a wood-derived ceramic material, to fabricate a wall-flow filter onto which ceria-based catalytic coatings are synthesised in-situ with two different morphologies. Based on laboratory tests performed emulating realistic conditions, it is shown that the deposition of a ceria washcoat on the substrate reduces the temperature needed to regenerate the filter by 14 degrees C to 110 degrees C. The use of a ceria morphology that enhances the soot/catalyst contact conditions strengthens this effect. The influence of the substrate arrangement on the regeneration performance and the oxidative capacity of the catalytic coating is analysed. These results extend the possibilities of further reducing the soot oxidation temperature by combining the synergistic effects of an engineered ceria morphology and an optimum substrate arrangement.