Catalysis with small free noble metal clusters

Thorsten M. Bernhardt, Liana D. Socaciu, Jan Hagen, Denisia Popolan, Jérôme Le Roux, Ulrich Heiz, Ludger Wöste

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

2 Scopus citations

Abstract

In general, reaction mechanisms in heterogeneous catalysis are difficult to reveal, because of the complexity of the reaction system. Our approach employs mass-selected metal clusters as well-defined model reaction centers. Chemical reactions on these clusters are investigated in a temperature controlled radio frequency (rf)-ion trap setup. Product ion concentrations as a function of storage time enable the determination of reaction kinetics and reaction mechanisms of free clusters. As an example, the CO combustion reaction on small gold clusters is studied. It is known that supported gold clusters with few atoms up to nm size exhibit relevant catalytic properties. Our ion trap measurements reveal catalytic activity already for negatively charged gold dimers. When the reaction kinetics are investigated as a function of temperature, an intermediate product with CO and O2 coadsorbed can be isolated. In contrast, small atomic silver clusters have not been found relevant for catalytic oxidation processes so far. Our investigations show for the first time evidence for a strongly size dependent catalytic activity of Agn-.

Original languageEnglish
Title of host publicationClusters and Nano-Assemblies
Subtitle of host publicationPhysical and Biological Systems: Richmond, Virginia, U.S.A., 10-13 November, 2003
PublisherWorld Scientific Publishing Co.
Pages1-9
Number of pages9
ISBN (Electronic)9789812701879
ISBN (Print)9812563318, 9789812563316
DOIs
StatePublished - 1 Jan 2005
Externally publishedYes

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