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氧化物负载的金催化剂具有温和条件下优异的CO催化氧化活性。实验与理论计算表明,金与氧化物两相界面在催化反应过程中具有重要地位。反相催化剂提供了全新的角度以探究界面的重要地位。本文以Au(111)表面负载Al_2O_3团簇为反相催化剂模型,基于密度泛函理论,对催化剂模型的构型、界面性质以及O_2、CO的吸附与氧化进行了理论计算与研究。理论计算表明:电荷的迁移增强了Al_2O_3小团簇在Au(111)表面的附着,在催化剂金表面与氧化铝的两相界面位置,Au原子与Al原子的协同作用使得氧分子易于在界面位置吸附,并因此高度活化。对催化CO氧化反应路径,分别计算了缔合机理和解离机理不同路径,从活化能分析表明缔合机理比解离机理更可能发生。本文的工作揭示了反相催化剂催化CO氧化的活性本质,表明两相界面在金催化CO氧化中具有重要作用。
Oxide supported gold catalysts have excellent CO catalytic oxidation activity under mild conditions. Experiments and theoretical calculations show that the interface between gold and oxide has an important role in the catalytic reaction. Reversed catalysts provide a completely new perspective to explore the importance of interfaces. In this paper, Al 2 O 3 clusters supported on Au (111) surface are used as the reverse phase catalyst model, and the theoretical calculations and studies on the configuration, interface properties and adsorption and oxidation of O 2 and CO are carried out based on the density functional theory. The theoretical calculations show that the charge transfer enhances the adhesion of Al 2 O 3 clusters on the surface of Au (111). The synergistic effect of Au atoms and Al atoms at the interface between the Au surface and the Au surface of the catalyst makes the oxygen molecules easy to bond at the interface Adsorbed, and therefore highly activated. For the catalytic CO oxidation reaction path, different paths of association and dissociation mechanisms were calculated respectively. Analysis of activation energy shows that the association mechanism is more likely to occur than the dissociation mechanism. The work in this paper reveals the catalytic nature of CO oxidation catalyzed by reversed-phase catalysts and shows that the two-phase interface plays an important role in gold-catalyzed CO oxidation.