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@Ce 0.5 Zr 0.5 O 2 /Al 2 O 3 catalyst with a core–shell structure were investigated for automobile three-way reactions and compared with those of Pd/Al 2 O 3, Pd@CeO 2 /Al 2 O 3, and Pd@ZrO 2 /Al 2 O 3 catalysts. TEM, HRTEM, and EDS mapping analyses showed that the core–shell structure of Pd@Ce 0.5 Zr 0.5 O 2 nanoparticles was intact after the hydrothermal treatment at 1050 °C for 5 h. Meanwhile, CO–DRIFT results suggested that the interface of Pd core and Ce 0.5 Zr 0.5 O 2 shell acted as the active sites in the reaction of three-way catalysts. Additionally, XPS, FT-IR, and CO–DRIFT analyses demonstrated that a large amount of OH groups were present on the surface of Pd@Ce 0.5 Zr 0.5 O 2 /Al 2 O 3 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@Ce 0.5 Zr 0.5 O 2 /Al 2 O 3 catalyst to keep the high catalytic activity after aging at high temperature.