COLL 205 |
| David C. Tang1, Kevin S. Hwang2, Miquel Salmeron3, and Gabor A Somorjai2. (1) Department of Chemistry/Gabor A. Somorjai Group, University of California, Berkeley, D56 Hildebrand Hall, Berkeley, CA 94720, (2) Department of Chemistry, University of California, Berkeley, CA 94720, (3) Materials Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Mail Stop 66, Berkeley, CA 94720 |
| What causes catalyst poisoning under reaction conditions is one of the most important and unresolved questions in catalysis science. During a catalytic reaction the catalyst surface is covered with a dense layer of adsorbates in equilibrium with the gas phase. This layer consists of reactive species, inactive spectator molecules, and poisoning adsorbates that can halt the reaction. Understanding the role of each adsorbed species as they compete for adsorption sites is key to ascertain the nature of poisoning and to design better catalysts. Here we report a scanning tunneling microscopy and mass spectrometry study that shows adsorbate mobility is essential for sustained catalytic activity on metal surfaces. Specifically, we show that poisoning of the ethylene hydrogenation on Rh(111) single crystal by CO occurs not simply due to the presence of poisoning molecules on the surface, but as a result of these adsorbates reducing surface mobility by forming static ordered structures. |
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Posters: Fundamental Research in Surface and Colloid Chemistry
6:00 PM-8:00 PM, Monday, March 29, 2004 Disneyland -- North Exhibit Hall, Poster
Division of Colloid and Surface Chemistry |