Co3O4/CeO2 andCo3O4/CeO2-ZrO2 composite catalysts for methane combustion:: Correlation between morphology reduction properties and catalytic activity

Co3O4/CeO2 and Co3O4/CeO2-ZrO2 composite catalysts have been prepared by two different techniques, co-precipitation by citrate method and impregnation with cobalt nitrate of pre-formed ceria and ceria-zirconia oxides. The materials, as prepared and after ageing at 750 ° C 7 h, were tested for methane combustion and the catalytic performances were compared with those of a commercial Co3O4, used as reference. A significant improvement of the activity was observed in the composite oxide Co3O4(30 wt%)/ CeO2(70 wt%), prepared by citrate method, which exhibits the lowest light-off temperature of methane (T-50 = 400 ° C and does not suffer deactivation after calcination at 750 ° C 7 h. © 2005 Elsevier B.V. All rights reserved.