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Dumbbell-like Au0.5Cu0.5@Fe3O4 Nanocrystals: Synthesis, Characterization, and Catalytic Activity in CO Oxidation

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journal contribution
posted on 2016-10-10, 00:00 authored by Sharif Najafishirtari, Tathiana Midori Kokumai, Sergio Marras, Priscila Destro, Mirko Prato, Alice Scarpellini, Rosaria Brescia, Aidin Lak, Teresa Pellegrino, Daniela Zanchet, Liberato Manna, Massimo Colombo
We report the colloidal synthesis of dumbbell-like Au0.5Cu0.5@Fe3O4 nanocrystals (AuCu@FeOx NCs) and the study of their properties in the CO oxidation reaction. To this aim, the as-prepared NCs were deposited on γ-alumina and pretreated in an oxidizing environment to remove the organic ligands. A comparison of these NCs with bulk Fe3O4-supported AuCu NCs showed that the nanosized support was far more effective in preventing the sintering of the metal domains, leading thus to a superior catalytic activity. Nanosizing of the support could be thus an effective, general strategy to improve the thermal stability of metallic NCs. On the other hand, the support size did not affect the chemical transformations experienced by the AuCu NCs during the activation step. Independently from the support size, we observed indeed the segregation of Cu from the alloy phase under oxidative conditions as well as the possible incorporation of the Cu atoms in the iron oxide domain.