Bare Ceria Formulations

The effect of crystallite size has been investigated by Kockrick et who compared soot combustion over cerium dioxide nanoparticles prepared by an inverse micro-emulsion synthesis and by a simple precipitation route. The results show that, besides there being a great difference in crystal size, the catalytic activity for fresh 

In addition to crystal size, the effect of surface area (SA) and porosity has also been investigated. It is generally shown that a reduction in surface area reduces Tf, this is especially true if ceria samples of the same origin are investigated (e.g. samples of ceria exposed to different aging temperatures) Rather scattered 

Palmisano etaV studied the influence of microstructure on soot activity. Ceria prepared by solution combustion synthesis (SCS) and 

The opposite results were found by Aneggi et aL, ° who studied the influence of pore size distribution on three samples of ceria, with the same surface area but prepared by different methods (Table 11.2). CA was a commercial sample prepared by a proprietary method and calcined at 773 K. CB was prepared according to a process that involved the precipitation of a homogeneous acidic solution of cerium nitrate with a base. The CC sample was freshly prepared by moderate calcination (473 K) of cerium carbonate obtained from Ce(NOs)3 by precipitation with NH4HCOS. Samples CB and CC have a smaller pore size (5-6 nm) than CA (14 nm) and 

Sample SA(m g- ) Average pore size (nm) Cumulative pore volume (cm .g ) 

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