Abstract

The effect of lower Cu (<= 30%) substitution on alkaline earth zirconate (A(1-x)Cu(x)ZrO(3)(-); A= Ca; Sr) perovskites prepared via a citrate route and calcined at 700 degrees C has been investigated as catalysts for total acetyl acetate combustion. The thermal behaviour indicates a beneficial effect of Cu in order to decrease the decomposition temperature of Ca and Sr zirconates. The characterization of the solids by atomic absorption spectroscopy (AAS), BET area, SEM, XRD, O-2-DTP and TPR indicates for the Sr series presence crystalline CuO phase in the copper strontium zirconates, meanwhile almost highly dispersed CuO is detected in the Ca series. Two effects explain the increases in the total acetylacetate combustion of Ca and Sr zirconates upon copper content. For one hand, in the Ca series, highly dispersed CuO phase, easier to be reduced increases the catalytic activity, meanwhile for the Sr series, a large extent of oxygen vacancies explains the catalytic effect.