Ceria-zirconia Nanocatalysts for Diesel Soot Combustion

A set of ceria-zirconia nanocatalysts with different Zr-contents and structural properties was prepared to study the effect of both the Zr-amount and surface-dependent activity towards soot combustion in “loose” and “tight” soot-catalyst contact. The properties of the catalysts were examined using several physico-chemical techniques. The best soot oxidation activities were achieved for the Ce_0.9Zr_0.1O₂-NP catalyst (NP means nano-polyhedra and 0.9 indicates the atomic ratio of Ce/Ce+Zr), due to its easier reducibility, compared to high-surface area catalysts with the same Ce/Zr ratio. Moreover, better performances were reached for Ce_0.9Zr_0.1O₂-NP, than similar nano-polyhedra with higher Zr-amounts (denoted as Ce_xZr_1-xO₂-NP, where x = 0.8 or 0.7). On the other hand, worse activities were obtained for both mesoporous and microporous catalysts with the same Ce/Zr ratio.