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Unravelling the Origin of the High-Catalytic Activity of Supported Au:  A Density-Functional Theory-Based Interpretation

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journal contribution
posted on 13.12.2006 by Norge Cruz Hernández, Javier Fdez. Sanz, José A. Rodriguez
Using first principles DF calculations we have studied the structural and catalytic properties of Au supported on TiOx−Mo(112) films. Our theoretical models are consistent with an initial (8 × 2) Mo(112)−Ti2O3 pattern which after Au deposition gives rise to ordered Au films that completely wet the surface. The oxidation of CO on model surfaces at coverage 1, 4/3, and 5/2 ML has been analyzed. The oxidation proceeds through a peroxo-like complex in which molecular oxygen is simultaneously bound to the CO and the surface. The energy barrier computed for a Au coverage of 4/3 ML is found significantly lower in agreement with the unusual high activity observed for this catalyst. The detailed analysis of the geometry and electronic structure provides a fundamental understanding of the reaction.