Comparison of effect of La-modification on the thermostabilities of alumina and alumina-supported Pd catalysts prepared from different alumina sources

摘要

The thermostability of La-free and La-modified aluminas derived from different alumina sources including pseudo-boehmite,aluminum sulfate,aluminum nitrate,and aluminum chloride have been studied by characterizationof BET specific surface area(BET) and X-ray powder diffracton(XRD).Further,theactivity and thermal durability of monolith-supported Pd catalysts using above different alumina as washcoats for simulatneously catalytic oxidation of (C_3H_8,C_3H_6 and CO have been investigatedusing continuous flowing reaction.The experimental results show that the oxidation activity over thealumina-supported Pd catalysts does not keep in agreement with the surface area of aluminas derived from four aluminum sources.Lanthanum modification improves the activity of all catalysts calcined over 1000degC for simultaneously catlaytic oxidatoin of C_3H_8 ,C_3H_6 and CO.Alumina source palys a role on the activity and thermostability of alumina andalumina-supported Pd catalysts.The experimental results show that pseudo boehmite is the best alumina source used for catalytic oxidation at high temperature over 1000degC.