STM studies of the structure of catalytically active gold

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Mingshu Chen, mschen@mail.chem.tamu.edu and D. Wayne Goodman, goodman@mail.chem.tamu.edu. Department of Chemistry, Texas A&M University, College Station, TX 77842
Previously, we have reported the synthesis of well-ordered Au mono- and bi-layer films on a TiOx/Mo(112).[M. S. Chen, D. W. Goodman, Science 2004, 306, 252] Kinetic measurements for the catalytic oxidation of carbon monoxide show that the Au bi-layer structure is significantly more active (by more than an order of magnitude) than the monolayer, and is about 45 times higher than that reported for the most active higher-surface-area Au/TiO2 catalyst. Here we report our recent STM studies of this system. The wetting of Au on the (8x2)-TiOx is clearly evidenced, and the ordered (1x1) mono- and (1x3) bi-layer structures are atomic resolved. The electronic and chemical properties of these ordered Au films have been characterized by IRAS using CO as a probe molecule and UPS. The common structural features of ordered Au bi-layers and Au bi-layer nanoparticles on TiO2(110) are described, and the exceptionally high catalytic activity of the Au bi-layer structure related to its unique electronic properties.