Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Cluster size effects on CO oxidation activity, adsorbate affinity, and temporal behavior of model Aun/TiO2 catalysts
 

Summary: Cluster size effects on CO oxidation activity, adsorbate affinity,
and temporal behavior of model Aun/TiO2 catalysts
Sungsik Lee, Chaoyang Fan, Tianpin Wu, and Scott L. Andersona
Department of Chemistry, University of Utah, 315 S. 1400 E. RM Dock, Salt Lake City,
Utah 84112-0850
Received 19 April 2005; accepted 21 July 2005; published online 28 September 2005
Model catalysts were prepared by deposition of size-selected Aun n=17 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. 2005 American
Institute of Physics. DOI: 10.1063/1.2035098
I. INTRODUCTION
The catalytic reactivity of small size gold particles on

  

Source: Anderson, Scott L. - Department of Chemistry, University of Utah

 

Collections: Energy Storage, Conversion and Utilization; Materials Science; Chemistry