Enhanced catalytic activity and thermal stability by highly dispersed Pd-based nanocatalysts embedded in ZrO2 hollow spheres

Sintering resistant noble metal nanoparticles are critical to the development of advanced catalysts with high activity and stability. Herein, we reported the construction of highly dispersed Pd nanoparticles loaded at the inner wall of ZrO₂ hollow spheres (Pd@HS-ZrO₂), which shows improved activity and thermal stability over references in the Pd-ZrO₂ (catalyst-support) system. Even after 800 °C high temperature calcination, the Pd nanoparticles and ZrO₂ hollow spheres did not undergo morphological changes. The Pd@HS-ZrO₂ manifests batter catalytic activity and thermal stability than the counterpart Pd/ZrO₂ catalysts. In comparison to Pd/ZrO₂-800, Pd@ZrO₂-800 exhibits a 25°C reduction in the temperature required for complete conversion of CO. The enhanced catalytic activity and thermal stability of Pd@HS-ZrO₂ can be attributed to the nanoconfinement effect offered by the 10 nm wall thickness of the ZrO₂ hollow spheres, which suppresses the coarsening of the Pd nanoparticles (active center for catalysis).