Studies on LaAlO_3 as a Second Support in the Combustion Catalyst

摘要

Cordierite is a good support of combustion catalyst for its thermostability and small thermodilatation coef. But the specific sarface area of cordierite is poor, which results in the performance of combustion catalysts is not good enough. Γ―Al_2O_3 has great surface area and is usually coated on the surface of cordierite as a second snpport. On the other hand, perovskite ― type LaMnO_3 and LaCoO_3 are active phases in the combustion catalysts. In this paper, LaAlO_3(LA) which substituted for γ―Al_2O_3 was coated on cordierite surface. When LaMnO_3 formed on the LaAlO_3 surface, it's activity was better than that of γ―Al_2O_3 or cordierite only, when LaCoO_3 formed on γ―A1_2O_3, cobalt ions could interact with γ― A1_2O_3 and spinel CoAl_2O_4―like to be formed which lead decreasing of combustion activity. If LaAlO_3 was used for second support, CoAl_2O_4 formation was avoided and good activity was obtaind.