Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-V-19leads to further lowing of CB combustion temperatures (Table). Despite that surface area ofMn-modified catalyst is less than of the pure support, it is more active than pure CeO 2 -ZrO 2 ,so manganese noticeably promotes soot oxidation. The positive influence of manganese in theprocess of CB combustion is also mentioned in the work [4]. Presence of two peaks on theDTA curves is discussed in literature [6]. We suppose them to be influenced by variousfactors: external surface area of the catalyst, which is available for the soot; extent ofimmediate contact CB with catalyst; oxygen mobility of the system.High catalytic activity of examined systems can obviously be explained taking intoconsideration method of catalyst preparing. As it’s known there are some mineral inclusionsin the pine sawdust [7], in particular ions K + and Ca 2+ , which are supposed to promotecatalytic oxidation of soot [2]. So the support is initially provided with these actives speciesdue to the method of synthesis. Besides according to data obtained with the help of SEM(Fig.1), using sawdust as matrix forpreparing the catalysts leads to biomorphicstructure of the final mixed oxides [8], i.e.they completely repeat the structure of thecellulose component of the wood. Thusobtained oxides exhibit besides high surfacearea also heightened shortness, whichfavours improving contact between soot andcatalyst and in this way decreases thetemperature of soot combustion.Fig. 1. SEM image of biomorphic CeO 2 -ZrO 2 .References1. Stratakis G.A., Stamatelos A.M. // Combustion and Flame. 2003. № 132. P. 157.2. Xiaodong Wu, Dongxu Liu, Duan Weng. // Catalysis Communications. 2007. V. 8 P. 1274-1278.3. Saab E., Abi-Aad E., Bokova M.N., Zhilinslaya E.A., Aboukais A. // Carbon. 2007. V. 45. P. 561-567.4. Saab E., Abi-Aad E., Zhilinskaya E., Aboukais A. // Catalysis Today. 2007. V. 119 P. 286-290.5. Liotta L.F., Macaluso A., Longo A. // Applied Catalysis A: General. 2003. V.240 P. 295-307.6. Neeft J., Hoornaert F., Makkee M., Moulijn J. // Thermochimica Acta. 1996. V. 287. P. 261-278.7. Cao J., Rambo C.R., Sieber H. // Ceramics International. 2004. V. 30. P. 1967-1970.8. Rambo C.R., Cao J., Sieber H. // Materials Chemistry and Physics. 2004. V. 87. P. 345-352.493