Deposition of nanophase doped-ceria systems on ceramic honeycombs for automotive catalytic applications

Due to the large number of lattice defects, nanophase ceria can provide a large number of active sites for gas–solid catalysis, especially if doped with other metal atoms of lower oxidation state. Therefore, if deposited properly upon honeycomb structures it can be used for high-temperature catalytic applications such as automobile catalysis, provided that it exhibits adequate thermal stability. The present work involves the characterization of nanophase ceria powders produced by chemical methods, with respect to thermal stability and their deposition upon cordierite honeycombs. It is shown that thermal stability can be enhanced significantly with the dispersion of ceria within a γ-alumina matrix. Ceria/γ-alumina layers were deposited on cordierite honeycombs either directly from the sol phase or from slurries of already calcined powders. The rheological characteristics were optimized for the deposition of an adequate amount of ceria in the form of a homogeneous layer.