Investigation of the Role of Surface Oxides in Catalysis by Gold Nanoparticles

In contrast to the long held view that gold is catalytically inert, it is now well known that supported gold nanoparticles are notably more active than other transition metals for low temperature catalytic oxidation of CO, as well as promoting several other catalytic reactions [1]. This has stimulated huge efforts in an attempt to understand the mechanisms responsible for the high activity, including investigations into the nature of oxygen on gold surfaces [2]. Through density-functional theory and the approach of \textit{ab initio} thermodynamics [3] we have found that on the gold (111) surface, thin oxide-like structures are significantly more stable for the pressure and temperature conditions of CO oxidation. The energetic preference for such partially oxidized gold, is in accord with very recent experimental results [4]. For the identified lowest energy surface oxide-like structure, we investigate the adsorption of CO on the surface and determine the reaction pathways for CO oxidation. \newline [1] Haruta, Catal. J. New. Mater. Electro. Sys. \textbf{7,} 163 (2004). \newline [2] R. Meyer \textit{et al}., Gold Bull. \textbf{37}, 72 (2004), and references therein. \newline [3] K. Reuter, C. Stampfl and M. Scheffler, in Handbook of Materials Modeling, Volume 1, Fundamental Models and Methods, Sidney Yip (Ed) 2005, 149-194. \newline [4] L. Fu \textit{et al.} J. Phys. Chem. B 109, 3704 (2005).