Systems based on Ce-Zr are used in catalytic converters for their oxygen storage ability. Recently, their application for soot abatement is under investigation. In this paper, preliminary results of the performance of Ce-Zr systems with the addition of K are reported by varying potassium content and calcination temperature. The powder catalysts were prepared by a variant of the citrates route developed at University of L'Aquila. Characterization of the catalysts after calcination was performed by different techniques: profile fitting of the XRD data, estimation of surface composition by XPS, evaluation of catalytic performance by temperature programmed oxidation tests of the soot-catalyst mixture and of redox properties by carbothermic reduction and subsequent oxidation in a high resolution thermobalance. The characterization by XRD showed that the system maintains the crystallographic structure Fm-3m and that the potassium is segregated on the grain boundaries. The catalytic activity results showed that the systems are particularly active even after 10 hours of calcination at 900 degrees C in fluidized bed. This temperature is high enough to get reasonably stable systems for practical applications. Moreover, the soot oxidation rate has a maximum at 368 degrees C in the sample with the best performance, therefore in the range of temperatures of diesel engine exhaust gases. The XPS data showed the presence of Ce, Zr, K and also of significant amount of Cl. Other formulations were prepared by adding small amounts of the different potassium halides.

Catalytic systems based on Ce, Zr, K for soot oxidation / R., Blasetti; F., Giannini; P., Viparelli; P. L., Villa; C., Bianchi; P., Ciambelli; G., Matarazzo; V., Palma; Russo, Paola. - 16:(2008), pp. 267-274. (Intervento presentato al convegno 2nd Advanced Atomspheric Aerosol Symposium (AAAS08) tenutosi a Naples, ITALY nel SEP 09-12, 2008).

Catalytic systems based on Ce, Zr, K for soot oxidation

RUSSO, PAOLA
2008

Abstract

Systems based on Ce-Zr are used in catalytic converters for their oxygen storage ability. Recently, their application for soot abatement is under investigation. In this paper, preliminary results of the performance of Ce-Zr systems with the addition of K are reported by varying potassium content and calcination temperature. The powder catalysts were prepared by a variant of the citrates route developed at University of L'Aquila. Characterization of the catalysts after calcination was performed by different techniques: profile fitting of the XRD data, estimation of surface composition by XPS, evaluation of catalytic performance by temperature programmed oxidation tests of the soot-catalyst mixture and of redox properties by carbothermic reduction and subsequent oxidation in a high resolution thermobalance. The characterization by XRD showed that the system maintains the crystallographic structure Fm-3m and that the potassium is segregated on the grain boundaries. The catalytic activity results showed that the systems are particularly active even after 10 hours of calcination at 900 degrees C in fluidized bed. This temperature is high enough to get reasonably stable systems for practical applications. Moreover, the soot oxidation rate has a maximum at 368 degrees C in the sample with the best performance, therefore in the range of temperatures of diesel engine exhaust gases. The XPS data showed the presence of Ce, Zr, K and also of significant amount of Cl. Other formulations were prepared by adding small amounts of the different potassium halides.
2008
2nd Advanced Atomspheric Aerosol Symposium (AAAS08)
04 Pubblicazione in atti di convegno::04b Atto di convegno in volume
Catalytic systems based on Ce, Zr, K for soot oxidation / R., Blasetti; F., Giannini; P., Viparelli; P. L., Villa; C., Bianchi; P., Ciambelli; G., Matarazzo; V., Palma; Russo, Paola. - 16:(2008), pp. 267-274. (Intervento presentato al convegno 2nd Advanced Atomspheric Aerosol Symposium (AAAS08) tenutosi a Naples, ITALY nel SEP 09-12, 2008).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/509588
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