Catalytic combustion of methane over lafeo3 perovskites: The influence of coprecipitation ph and ageing time

GINA PECCHI ^[1] ; PATRICIO REYES ^[1] ; RAÚL ZAMORA ^[1] ; LUIS E CADÚS ^[2] ; BIBIANA P BARBERO ^[2]
1. [1] Universidad de Concepción
  
  Universidad de Concepción
  
  Comuna de Concepción, Chile
2. [2] Universidad Nacional de San Luis
  
  Universidad Nacional de San Luis
  
  Argentina
Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 51, Nº. 4, 2006, págs. 1001-1005
Idioma: inglés
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Resumen
- The aim of this work was to study the effect of two precipitation pHs and three different ageing times on the preparation of simple LaFeO3 perovskites for their use as catalysts in the methane combustion. Absorption atomic spectroscopy (AAS), BET specific area measurements, XRD analysis, Raman, XPS, TGA and DTA analysis, TPR and TPO profiles revealed that significant changes in chemical composition, surface area and surface composition was produced at pH 8 when the ageing time was changed, leading to solids with different catalytic activity in methane combustion. At the higher precipitation pH studied, pH 10, the physical chemistry properties for all the samples obtained at different ageing times are almost identical, and therefore the solids exhibit similar activities in the combustion reaction. The catalysts were found to be active for methane combustion, and the effect of the perovskites structure and surface properties became more important