Document Detail


Cluster size effects on CO oxidation activity, adsorbate affinity, and temporal behavior of model Au(n)/TiO2 catalysts.
MedLine Citation:
PMID:  16392514     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
Model catalysts were prepared by deposition of size-selected Au(n) (n = 1-7) on rutile TiO2(110), and characterized by a combination of electron spectroscopy, ion scattering, temperature-programmed desorption, and pulse-dosing mass spectrometry. CO oxidation activity was found to vary strongly with deposited cluster size, with significant activity appearing at Au3. Activity is not obviously correlated with affinity for CO, or with cluster morphology, but is strongly correlated with the clusters' ability to bind oxygen (during O2 exposure) on top of the gold. The temporal dependence of CO2 evolution in reaction of O2 pre-exposed samples with CO pulses shows an interesting cluster size dependence. For Au5 and Au6, the peak CO2 production is coincident with the peak CO flux, but for Au3, Au4, and Au7, there are significant induction periods for CO2 evolution. In addition, it is observed that some of the most active cluster sizes have the slowest CO2 evolution rates. Several mechanistic scenarios capable of accounting for the observations are laid out.
Authors:
Sungsik Lee; Chaoyang Fan; Tianpin Wu; Scott L Anderson
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of chemical physics     Volume:  123     ISSN:  0021-9606     ISO Abbreviation:  J Chem Phys     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2006-01-05     Completed Date:  2007-07-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0375360     Medline TA:  J Chem Phys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  124710     Citation Subset:  -    
Affiliation:
Department of Chemistry, University of Utah, 315 S. 1400 E. RM Dock, Salt Lake City, Utah 84112-0850, USA.
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