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Theoretical studyo f structure and catalytic properties of gold and bimetallic clustersтезисы доклада
- Авторы: Mukhamedzyanova D.F., Pichugina D.A., Beletskaya A.V., Askerka M.S., Shestakov A.F., Kuz’menko N.E.
- Сборник: Faraday Discussion 152: Gold
- Тезисы
- Год издания: 2011
- Место издания: Gardiff, UK
- Первая страница: 20
- Последняя страница: 20
- Аннотация: In order to study the nature of gold active sites quantum-chemical calculations of Aun and AunMem (Me = Ni, Pd) clusters and simulation of catalytic (i) direct hydrogen peroxide formation and (ii) allylbenzene double-bond migration processes have been performed. (i) The study of oxygen and hydrogen adsorption shows that their activation occurs at the atoms with higher electron density. The formation of structures containing bridge or molecular oxygen is more possible. The interaction of hydrogen molecule with cluster occurs with H−H bond rupture. Mixed Au4Pd4 cluster demonstrates higher catalytic activity in the direct synthesis of hydrogen peroxide than the Au8 cluster, because in the case of Au4Pd4 energy barrier of hydrogen atom migration to the ООН∙ (36 kJ/mol), leading to the formation of H2O2, is about two times lower than in the case of Au8 cluster (83 kJ/mol). (ii) Activation of allylbenzene double-bond through π-complex formation is observed at low-coordinated gold atoms (corner and edge atoms of a cluster). Allylbenzene double-bond migration is more favorable on positive charged atoms of gold clusters via metal-allylic mechanism. Thus, according to the calculation, Auδ+ sites are the most active in double-bond migration. The redistribution of atomic charges in gold-containing nanoparticles is crucial in catalytic reactions, and can be varied depending on the active sites of a catalyst in the specific reaction.
- Добавил в систему: Пичугина Дарья Александровна