ChemInform Abstract: Effect of Structural Modification on the Catalytic Property of Mn-Substituted Hexaaluminates.

ChemInform Abstract

The effect of partial substitution of the mirror plane cations in Mn-substituted hexaaluminates (A_1-xB_xMnAl₁₁O_19-y with A: Ba, Sr, Ca, La, K and B: Sr, La, K, Ca) on the catalytic activity for the combustion of methane and the specific surface area is studied. In particular, partial substitution of Sr for La (i.e., Sr_1-xLa_xMnAl₁₁O_19-y) is found to result in a large surface area (23.8 m²/g for x = 0.2) and a low ignition temp. (T_10% = 500 °C) after calcination at 1300 °C. The effect of this substitution appears to be the suppression of crystal growth along the c-axis which results in a higher surface area and an increase in the oxidation state of Mn which promotes active oxygen desorption.