Self-Assembled Pd@CeO2/γ-Al2O3 Catalysts with Enhanced Activity for Catalytic Methane Combustion

5 years ago

Self-Assembled Pd@CeO2/γ-Al2O3 Catalysts with Enhanced Activity for Catalytic Methane Combustion

Zheng Zhang, Wang Li, Dapeng Liu, Yang Duan, Xilan Feng, Yu Zhang

Pd@CeO2/Al2O3 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-Al2O3. A model reaction of catalytic methane-combustion is employed here to evaluate the three Pd@CeO2/γ-Al2O3 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. Pd@CeO2 nanospheres are supported on γ-Al2O3 via three methods, including electrostatic interaction, supramolecular self-assembly, and physical mixing. Due to strong metal–support interaction, a sample of Pd@CeO2/γ-Al2O3 prepared by supramolecular self-assembly demonstrates the optimized catalytic performance toward catalytic methane combustion, which has a relative low light-off temperature (T50 of about 364 °C).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/smll.201700941