Effect of ag addition on the thermal stability and catalytic properties of lafeo3 perovskite

• F RIOSECO ^[1] ; L RADOVIC ^[1] ; X GARCÍA ^[1] ; A GORDON ^[1] ; G PECCHI ^[1]
  1. [1] Universidad de Concepción

     Universidad de Concepción

     Comuna de Concepción, Chile

     
• Localización: Journal of the Chilean Chemical Society (Boletín de la Sociedad Chilena de Química), ISSN-e 0717-6309, ISSN 0366-1644, Vol. 55, Nº. 1, 2010, págs. 44-49
• Idioma: inglés
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• Resumen

  • The effect of low Ag substitution in LaFeO3 perovskite on the thermal stability and catalytic oxidation of toluene was studied. Perovskites of the type La1-xAg xFeO3 (xAg =0.0, 0.05, 0.10) were prepared by the amorphous citrate method; characterized by nitrogen adsorption, XRD, FTIR, SEM-EDAX, TPR and O2- TPD techniques; and tested for the catalytic combustion of toluene in a flow reactor under excess oxygen. In comparison with the pure perovskite LaFeO3, the partially substituted La1-xAg xFeO3 present a perovskite structure with well-defined crystalline phases and greater reduction ability (attributable to the redox pair Fe+3/Fe+4). Noticeable changes in the á and ß-oxygen contents upon silver substitution were detected. Larger content of á-oxygen in the pure LaFeO3 perovskite is associated with greater catalytic activity. Two important effects upon Ag substitution in a pure LaFeO3 perovskites were observed: i) a greater reduction ability, ii) higher occurrence of oxygen vacancies due to ß-oxygen desorption, which were not active in the studied reaction.