AVS 51st International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThM

Paper SS1-ThM7
The Role of Defects in the Nucleation, Structure, and Stability of Gold Clusters on Titania

Thursday, November 18, 2004, 10:20 am, Room 210B

Session: Metal Oxide and Clusters III: Supported Cluster Formation and Reactivity
Presenter: W.T. Wallace, Texas A&M University
Authors: W.T. Wallace, Texas A&M University
M.-S. Chen, Texas A&M University
B.K. Min, Texas A&M University
K.K. Gath, Texas A&M University
D.W. Goodman, Texas A&M University
Correspondent: Click to Email
The discovery that Au clusters dispersed on certain metal oxides are efficient catalysts for a variety of low-temperature reactions has stimulated extensive study with the goal of developing a new generation of superior, Au-based catalysts. In this study, the interaction of Au with titania, a commonly used industrial support, has been addressed. Titania, as a 3-D cluster, or a titanium cation, introduced as a heterogeneous defect into a silica thin film, acts as a nucleation site for Au clusters, leading to an enhanced cluster density. Furthermore, both types of defects inhibit Au cluster sintering under reaction pressures and temperatures, thereby circumventing a serious limitation of the typical nanostructured Au catalysts. The growth mode of Au deposited onto titania thin films grown on Mo(112) illustrates the crucial role of surface structure on the Au morphology. On titania films grown on Mo(100), Au forms 3-D clusters when annealed, whereas on a highly defective titania surface grown on Mo(112), Au grows layer-by-layer, forming a thin, ordered film that exhibits exceptional catalytic activity toward CO oxidation.