Soot oxidation catalysts perovskite-type oxides

Catalytic combustion of diesel soot particulates over LaMnOs perovskite-type oxides prepared by malic acid method has been studied. In the LaMn03 catalyst, the partial substitution of alkali metal ions into A site enhanced the catalytic activity in the combustion of diesel soot particulates and the activity was shown in following order Cs>K>Na. In the LarxCs MnOj catalyst, the catalytic activity increased with an increase of X value and showed constant activity at the substitution of x>0.3... 

Several researchers have focused their attention on the application of oxide materials to lower the oxidation temperature of soot particulates. It was reported that active soot oxidation catalysts are PbO, C03O4, V2O5, M0O3, CuO, and perovskite type oxides[3]. 

SIMULTANEOUS NOx REDUCTION AND SOOT ELIMINATION FROM DIESEL EXHAUST ON PEROVSKITE-TYPE OXIDE CATALYSTS... 

Zheng, J., Liu, J., Zhao, Z., Xu, J., Duan, A., and Jiang, G. (2012) The synthesis and catalytic performances of three-dimensionally ordered macroporous perovskite-type LaMni- Fe Oa complex oxide catalysts with different pore diameters for diesel soot combustion. Catal Today, 191,146-153. 

Potassium- and strontium-substituted praseodymium manganate Pro,7Sro,2Ko,iMn03 perovskite-type catalysts were explored in supported form on ceramic foam filters for soot oxidation in typical conditions of a diesel engine [55]. Compared to bare soot oxidation reaction, the soot oxidation in the presence of these catalysts corresponded to a decrease of the Tinitiai value by 150 °C and Tfinai value by 100 °C. Besides the activity, another advantage of the system is the very good thermal stability. 

Teraoka, Y., and Labhsetwar, N. (2013) Bench scale experiments of diesel soot oxidation using Pro,7Sro.2Ko.iMn03 perovskite type catalyst coated on ceramic foam filters. Top. Catal, 56 (18), 457-461. 

The formation of perovskite structures does not always have a positive effect on the soot combustion activity of mixed oxides, and a few examples of catalyst deactivation due to perovskite structure formation have been reported. The stability of Ba, Isoot combustion, was studied. This catalyst was thermally stable after 30 h at 800 °C, but above 830 °C catalyst deactivation due to BaCe03 perovskite structure formation was observed [46]. Ba/Mn-Ce catalysts were also tested for soot oxidation in the presence of NO,c> concluding that the formation of perovskite-type oxides after the high-temperature calcination caused the loss of NO storage capacity and a small increase in soot oxidation temperature, but did not seem to affect the NO oxidation activity [47]. 

Highly active Lai K Co03 perovskite-type complex oxide catalysts for the simultaneous removal of diesel soot and nitrogen oxides under loose contact conditions. Catal. Lett., 124, 91-99. 

Wang, H., Liu, J., Zhao, Z, Wei, Y., and Xu, C. (2012) Comparative study of nanometric Co-, Mn- and Fe-based perovskite-type complex oxide catalysts for the simultaneous elimination of soot and NO from diesel engine exhaust. Catal. Today, 18 288-300. 

Three-dimensionally ordered macroporous LaCo Fei 03 perovskite-type complex oxide catalysts for diesel soot combustion. Catal. Today, 153, 136-142. 

Y.N., Duan, A.J., and Jiang, G.Y. (2010) Macroporous perovskite-type complex oxide catalysts of Lai K Coi Fej,03 for diesel soot combustion. /. Rare Earth, 27, 955-960. 

Zhang, G., Zhao, Z., Liu, J., et al. (2009). Macroporous Perovskite-type Complex Oxide Catalysts of Lai xkxCOi Yfey03 for Diesel Soot Combustion, J. Rare Earths, 27, pp. 955-960. 

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