Soot combustion and oxidation

Catalyst Method of preparation BETSA (mlg- ) Combusted material Tlo (°C) Reference 

Environmental transmission electron microscopy (ETEM) allows direct observation of the soot/catalyst interface to monitor in situ oxidation of the soot. Thermogravimetric (TG) and temperature-programmed methods have been used to study soot combustion in the presence and absence of oxygen, and the properties depend on the accessibility of gaseous oxygen and the location, shape and dimension of the ceria/soot interface (Fig. 8.26). Instead of using ceria on its own as a catalyst for soot oxidation, more studies have 

As mentioned earlier, a ceria-zirconia solid solution promotes bulk oxygen mobility. Different compositions at different calcination temperatures affect soot combustion, as proposed by Aneggi et aV- and as shown in Fig. 8.27. 

Soot combustion depends on the nature of the catalyst material and the type of soot. Atribak et prepared Ceo,76Zro 2402 catalysts by co-precipitation (CP) and reverse microemulsion (RME) having BET surface areas of 67 and 128 m. g respectively. The activity of a commercial catalyst from Rhodia (RH) (Ceo ysZrg 25O2, 113 rn. g ) was also used in testing. The catalytic activity of the various Ce-Zr catalysts tested was in the order RH RME CP. This trend can be explained based on the chemical properties of the catalysts rather 

It was reported that CeOg-FcgOg mixed oxides improve the kinetic performance of soot combustion. The reaction proceeds through a redox cycle between Ce VFe and Ce VFe , and FcgOg has been shown to exhibit a push-pull redox mechanism for soot combustion at higher temperatures. The active sites involved are Fe-O-Ce-type species. The mechanism shown in Fig. 8.29 involves the surface oxide anion bound to the Fe , which reacts with the soot 

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