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Shape- and size-specific chemistry of Ag nanostructures in catalytic ethylene epoxidation

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TLDR
In this article, shape and size controlled synthesis of Ag nanoparticles is used to show that silver nanocubes exhibit higher selectivity than nanowires and nanospheres for a given shape, larger particles offer improved selectivity.
Abstract
Catalytic selectivity in the epoxidation of ethylene to form ethylene oxide on alumina-supported silver catalysts is dependent on the geometric structure of catalytically active Ag particles and reaction conditions. Shape and size controlled synthesis of Ag nanoparticles is used to show that silver nanocubes exhibit higher selectivity than nanowires and nanospheres. For a given shape, larger particles offer improved selectivity. The enhanced selectivity toward ethylene oxide is attributed to the nature of the exposed Ag surface facets; Ag nanocubes and nanowires are dominated by (100) surface facet and Ag nanospheres are dominated by (111). Furthermore, the concentration of undercoordinated surface sites is related to diminished selectivity to ethylene oxide. We demonstrate that a simple model can account for the impact of chemical and physical factors on the reaction selectivity. These observations have also been used to design a selective catalyst for the ethylene epoxidation reaction.

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References
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Shape-Controlled Synthesis of Gold and Silver Nanoparticles

TL;DR: Monodisperse samples of silver nanocubes were synthesized in large quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP), characterized by a slightly truncated shape bounded by {100, {110}, and {111} facets.
Journal ArticleDOI

Towards the computational design of solid catalysts

TL;DR: The first steps towards using computational methods to design new catalysts are reviewed and how, in the future, such methods may be used to engineer the electronic structure of the active surface by changing its composition and structure are discussed.
Journal ArticleDOI

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

TL;DR: This Review will compare the results obtained from different systems and try to give a picture on how different types of metal species work in different reactions and give perspectives on the future directions toward better understanding of the catalytic behavior of different metal entities in a unifying manner.
Journal ArticleDOI

Shape-Controlled Synthesis of Colloidal Platinum Nanoparticles

TL;DR: Tetrahedral, cubic, irregular-prismatic, icosahedral, and cubo-octahedral particle shapes were observed, whose distribution was dependent on the concentration ratio of the capping polymer material to the platinum cation.
Journal ArticleDOI

The impact of nanoscience on heterogeneous catalysis

TL;DR: Advances in characterization methods have led to a molecular-level understanding of the relationships between nanoparticle properties and catalytic performance, and this knowledge is contributing to the design and development of new catalysts.
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