Preparation of alumina-supported Pd and LaMnO3 catalysts with the site-selective deposition and their catalytic activity for NO-CO reaction

摘要

By the combination of the preparation techniques of intra-pore deposition of Pd and selective intra/extra-pore deposition of LaMnO3, two types of alumina supported Pd-LaMnO3 catalysts were successfully obtained. It was suggested from the reduction behavior of supported Pd-LaMnO3 catalysts that when both Pd and LaMnO3 coexisted in the alumina pores (Pd/LaMnO3/Al2O3), Pd and LaMnO3 existed in close proximity each other to appear the interaction and that when Pd and LaMnO3 exist separately in and out of alumina pores, respectively (LaMnO3out/Pd/Al2O3), the existing environment of Pd was similar to that in Pd/Al2O3. For NO-CO reaction, Pd/Al2O3 and LaMnO30ut/Pd/Al2O3 showed comparable activity and N2/N2O selectivity, and Pd/LaMnO3/Al2O3 showed higher activity than and different N2/N2O selectivity from the two catalysts, revealing that the intimate Pd-LaMnO3 interaction is effective to modify the catalytic property of Pd species. The excellent catalytic property of Pd/LaMnO3/Al2O3 was sustained up to 800癈 of calcination temperature.