Practical Application and Improvement of Soot Oxidation Catalysts

Practical Application and Improvement of Soot Oxidation Catalysts 

Several examples of practical applications and improvement of soot oxidation catalysts, based on the mechanisms discussed, will be explained in this section. 

Junko Uchisawa, Akira Obuchi and Tetsuya Nanba 

Application of mobile catalysts is attractive because this type of catalyst is generally composed of base metal elements rather than expensive precious metals and exhibits good low temperature activity. However, practical application has not been realized because these catalysts easily move away from the support and DPF. Although several attempts have been made to overcome this problem, it may be fundamentally incompatible to simultaneously obtain high mobility (i.e., high activity) and good durability in such a catalyst. Panasonic has recently announced a DPF system that uses a PM oxidation catalyst containing an alkaline metal as an active component. They claim to have obtained almost identical performance at temperatures approximately 100°C lower than the conventional Pt catalyst. However, the stability and durability of the catalyst is yet to be confirmed. 

FBCs with other metal components, such as Pt, Mn, and Fe, have also been reported. The Rhodia group has developed and provided Fe and Ce-combined FBCs, and more recently a Fe-based FBC, which is no longer combined with Ce. The use of Fe-FBC together with a catalyzed DPF is more effective than the Fe-FBC alone. 

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