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 l arge number of active sites for gas-solid catalysis, especially if doped wi th other metal atoms of lower oxidation state. Therefore, if deposited prop erly upon honeycomb structures it can be used for high-temperature catalyti c applications such as automobile catalysis, provided that it exhibits adeq uate thermal stability. The present work involves the characterization of n anophase ceria powders produced by chemical methods, with respect to therma l stability and their deposition upon cordierite honeycombs. It is shown th at thermal stability can be enhanced significantly with the dispersion of c eria within a gamma -alumina matrix. Ceria/gamma -alumina layers were depos ited on cordierite honeycombs either directly from the sol phase or from sl urries of already calcined powders. The rheological characteristics were op timized for the deposition of an adequate amount of ceria in the form of a homogeneous layer. (C) 2000 Elsevier Science B.V. All rights reserved.