Self-Assembled Pd@CeO₂ /γ-Al₂ O₃ Catalysts with Enhanced Activity for Catalytic Methane Combustion

Pd@CeO₂ /Al₂ O₃ catalysts are of great importance for real applications, such as three-way catalysis, CO oxidation, and methane combustion. In this article, the Pd@CeO₂ core@shell nanospheres are prepared via the autoredox reaction in aqueous phase. Three kinds of methods are then employed, that is, electrostatic interaction, supramolecular self-assembly, and physical mixing, to support the as-prepared Pd@CeO₂ nanospheres on γ-Al₂ O₃ . A model reaction of catalytic methane-combustion is employed here to evaluate the three Pd@CeO₂ /γ-Al₂ O₃ samples. As a result, the sample Pd@CeO₂ -S-850 prepared via supramolecular self-assembly and calcined at 850 °C exhibits superior catalytic performance to the others, which has a far lower light-off temperature (T₅₀ of about 364 °C). Moreover, almost no deterioration of Pd@CeO₂ -S-850 is observed after five sequent catalytic cycles. The analysis of H₂ -TPR curves concludes that there exists hydrogen spillover related to the strong metal-support interaction between Pd species and oxides. The strong metal-support interaction and the specific surface areas might be responsible for the catalytic performance of the Pd@CeO₂ samples toward catalytic methane combustion.