Unravelling the Origin of the High-Catalytic Activity of Supported Au: A Density-Functional Theory-Based Interpretation
journal contributionposted on 13.12.2006 by Norge Cruz Hernández, Javier Fdez. Sanz, José A. Rodriguez
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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.