REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES

The reaction kinetics of methane combustion over La1-xCa xFeO3 perovskites (x=0.0, 0.2, 0.4) was studied. The results show that the catalytic activity is higher in the calcium-doped perovskites. It is found that this higher catalytic activity is related to a lower activation energy. The value of the...

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Autores principales:	PECCHI,GINA, JILIBERTO,M. GRACIELA, DELGADO,EDUARDO J
Lenguaje:	English
Publicado:	Sociedad Chilena de Química 2011
Materias:	methane combustion perovskite defects kinetic
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072011000400016
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spelling	oai:scielo:S0717-970720110004000162012-03-06REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITESPECCHI,GINAJILIBERTO,M. GRACIELADELGADO,EDUARDO J methane combustion perovskite defects kinetic The reaction kinetics of methane combustion over La1-xCa xFeO3 perovskites (x=0.0, 0.2, 0.4) was studied. The results show that the catalytic activity is higher in the calcium-doped perovskites. It is found that this higher catalytic activity is related to a lower activation energy. The value of the activation energy is not affected by the level of Ca-doping. The observed difference in the catalytic activity between the doped perovskites is interpreted as a consequence of the so-called compensatory effect, i.e., a larger pre-exponential factor which results from the higher number of active sites promoted by defect reactions triggered by the substitution of lanthanum by calcium. The substitution of lanthanum by a lower valence cation, as calcium, entails both the formation of oxygen vacancies and oxidation of some iron ions from Fe3+ to Fe4+, in order to preserve the electroneutrality. The oxygen vacancies account for the increasing participation of lattice oxygen in the combustion kinetics as the calcium doping increases. The experimental results were satisfactorily fitted to the Rideal-Elay mechanism.info:eu-repo/semantics/openAccessSociedad Chilena de QuímicaJournal of the Chilean Chemical Society v.56 n.4 20112011-12-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072011000400016en10.4067/S0717-97072011000400016
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	methane combustion perovskite defects kinetic
spellingShingle	methane combustion perovskite defects kinetic PECCHI,GINA JILIBERTO,M. GRACIELA DELGADO,EDUARDO J REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES
description	The reaction kinetics of methane combustion over La1-xCa xFeO3 perovskites (x=0.0, 0.2, 0.4) was studied. The results show that the catalytic activity is higher in the calcium-doped perovskites. It is found that this higher catalytic activity is related to a lower activation energy. The value of the activation energy is not affected by the level of Ca-doping. The observed difference in the catalytic activity between the doped perovskites is interpreted as a consequence of the so-called compensatory effect, i.e., a larger pre-exponential factor which results from the higher number of active sites promoted by defect reactions triggered by the substitution of lanthanum by calcium. The substitution of lanthanum by a lower valence cation, as calcium, entails both the formation of oxygen vacancies and oxidation of some iron ions from Fe3+ to Fe4+, in order to preserve the electroneutrality. The oxygen vacancies account for the increasing participation of lattice oxygen in the combustion kinetics as the calcium doping increases. The experimental results were satisfactorily fitted to the Rideal-Elay mechanism.
author	PECCHI,GINA JILIBERTO,M. GRACIELA DELGADO,EDUARDO J
author_facet	PECCHI,GINA JILIBERTO,M. GRACIELA DELGADO,EDUARDO J
author_sort	PECCHI,GINA
title	REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES
title_short	REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES
title_full	REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES
title_fullStr	REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES
title_full_unstemmed	REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES
title_sort	reaction kinetics of methane combustion over la1-x ca feo3 perovskites
publisher	Sociedad Chilena de Química
publishDate	2011
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072011000400016
work_keys_str_mv	AT pecchigina reactionkineticsofmethanecombustionoverla1xcafeo3perovskites AT jilibertomgraciela reactionkineticsofmethanecombustionoverla1xcafeo3perovskites AT delgadoeduardoj reactionkineticsofmethanecombustionoverla1xcafeo3perovskites
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REACTION KINETICS OF METHANE COMBUSTION OVER La1-x Ca FeO3 PEROVSKITES

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