SiO2@Pd@CeO2 catalyst with improved thermal stability: Effect of interaction between Pd and CeO2 on activity for CO oxidation

Abstract In this study, SiO2-supported Pd catalyst (Pd/SiO2) and CeO2-encapsulated Pd/SiO2 core-shell catalysts (SiO2@Pd@CeO2) were prepared and examined for CO oxidation. After aging at 700 ℃, the thermal stability of SiO2@Pd@CeO2 catalyst was improved in comparison to Pd/SiO2 because the CeO2 shell increased the structural stability and effectively inhibited the sintering of Pd particles on SiO2. Moreover, the differences in activity and properties of the catalysts were investigated through various characterization methods. The CeO2 shell induced changes in the chemical properties of the Pd particles adjacent to CeO2 due to the strong interaction between Pd and CeO2 (PdxCe1-xO2 solid solution), and the interaction improved the activity of the SiO2@Pd@CeO2 catalysts. As a result, the SiO2@Pd@CeO2 core-shell catalysts have an enhanced thermal stability and catalytic activity resulting from both a morphology effect and a synergistic effect between Pd and CeO2.