CO Oxidation on Au_n/TiO₂ Catalysts Produced by Size-Selected Cluster Deposition

Abstract

Planar model catalysts were prepared by deposition of size-selected gold clusters containing up to seven atoms on rutile TiO2 (110). Molecular oxygen is observed to bind inefficiently to the surface, probably at oxygen vacancies, and some oxygen also appears to bind to the gold clusters. Stable CO binding is observed atop gold for catalysts prepared by Au and Au2 deposition, but not for larger Aun. CO oxidation activity is strongly dependent on cluster size, with Au7-prepared samples >50 times more reactive than samples prepared by Au or Au2 deposition

Catalytically Active Gold: From Nanoparticles to Ultrathin Films

“…The unique activities of highly dispersed nanosized Au particles on oxide surfaces [1][2][3][4][5][6][7][8][9][10][11][12][13][14]42 are found to strongly correlate with the Au particle size; for example, the highest turnover frequency (TOF, reaction rate per surface Au site per second) occurs at a particle size of ∼3 nm. A model catalytic system, Au/TiO 2 (110), was used to investigate this unusual catalytic phenomenon under realistic reaction conditions.…”

Sub‐Nano Clusters: The Last Frontier of Inorganic Chemistry

“…This is well-recognized, as can be seen even just from the publications on catalytic properties of clusters toward the reaction of CO oxidation Arenz et al 2006;Metiu 2006, 2008;Haruta and Date 2001;Heiz et al 1999;Kaden et al 2009;Landman et al 2007;Lee et al 2004;Lopez and Norskov 2002;Molina and Hammer 2005;Remediakis et al 2005;Sanchez et al 1999;Tang and Henkelman 2009;Valden et al 1998;Yoon et al 2005;Yoon et al 2012;Zhai et al 2010;Zhang and Alexandrova 2013). Indeed, many corner and edge sites and the availability of dangling orbitals for potential substrate binding, high strain for higher reactivity, and tunability of the electronic structure of clusters via their size, composition, and the environment all point at their potential to be good catalysts.…”

“…Anderson et al (Kaden et al 2009;Lee et al 2004) address the electronic structure -catalytic property dependences explicitly. They prepared size-selected clusters of Pd and Au deposited on TiO 2 (110), and measured their catalytic activity toward the reaction of CO oxidation as a function of cluster size (Figure 14).…”

“…For example, clusters can be catalytic, (Arenz et al 2006;Chrétien and Metiu 2006;Haruta and Date 2001;Heiz et al 1999;Kaden et al 2009;Lee et al 2004;Lopez and Norskov 2002;Molina and Hammer 2005;Remediakis et al 2005;Sanchez et al 1999;Vajda et al 2009;Valden et al 1998;Yoon et al 2005;Zhai et al 2010) some clusters can be incorporated into materials as building blocks or ligands, (Alexandrova et al 2005;Alexandrova et al 2006;Claridge et al 2009;Fehlner et al 2005;Fokwa and Hermus 2012; Guennic et al 2004;Jadzinsky et al 2007;Reber et al 2007) and certain clusters can be high-temperature superconductors (de Heer 1993;Kresin 2012;Kresin andOvchinnikov 2008, 2012). Albeit, these applications often result from exhaustive searches for suitable cluster-containing materials, without much rationale.…”

Catalytic oxidation of cyclohexane by size-selected palladium clusters pinned on graphite

“…In the past decade, many studies have shown that under controlled environments (ultrahigh vacuum) the catalytic performance of these model systems can be modified by the size [7][8][9][10] and chemical composition of the active centres (nanoparticles/clusters) [11,12] as well as the nature of the support materials. [13][14][15] However, also essential to the creation of more efficient catalyst materials is their stability and catalytic performance under more practical conditions, factors which may also vary significantly during the course of the reaction.…”