Hydrothermal Stability of Core-Shell Pd@Ce0.5Zr0.5O2/Al2O3 Catalyst for Automobile Three-Way Reaction

In this paper, the hydrothermal stability and catalytic activity of Pd@Ce0.5Zr0.5O2/Al2O3 catalyst with a core-shell structure were investigated for automobile three-way reactions and compared with those of Pd/Al2O3, Pd@CeO2/Al2O3, and Pd@ZrO2/Al2O3 catalysts. TEM, HRTEM, and EDS mapping analyses showed that the core-shell structure of Pd@Ce0.5Zr0.5O2 nanoparticles was intact after the hydrothermal treatment at 1050 degrees C for S h. Meanwhile, CO-DRIFT results suggested that the interface of Pd core and Ce0.5Zr0.5O2. shell acted as the active sites in the reaction of three-way catalysts. Additionally, XPS, FT-M and CO-DRIFT analyses demonstrated that a large amount of OH groups were present on the surface of Pd@Ce0.5Zr0.5O2/Al2O3 catalyst, which could accelerate the decomposition of carbonate species and reduce the activation energy of the catalytic reaction. This was an important reason for the Pd@Ce0.5Zr0.5O2/Al2O3 catalyst to keep the high catalytic activity after aging at high temperature.