Comparative Study of Au/TiO2 and Au/ZrO2 Catalysts for Low-Temperature CO Oxidation

Grunwaldt, Jan‐Dierk; Maciejewski, Marek; Becker, Olav Sven; Fabrizioli, Patrizia; Baiker, Alfons

doi:10.1006/jcat.1999.2564

Cited by 330 publications

(242 citation statements)

References 39 publications

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“…1c and d represents the colloids prepared by the ''standard'' recipe [6,56] and also exhibit a very homogeneous size distribution (mean particle size 2.1 nm, standard deviation 0.7 nm). Immobilization of these colloids on TiO 2 and CeO 2 was also studied by means of STEM to verify the size of the particles after the immobilization on the support (for STEM images of this catalyst consult references [55,62]). The selection of the support is critical as different materials exhibit different ''aurophilicities,'' hence the adsorption of an identical colloid can lead to a strong deviation in the final particle size obtained due to a higher or lower critical contact angle with the support [55].…”

Section: Resultsmentioning

confidence: 99%

Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol: Effect of Gold Particle Size on Activity and Selectivity in Different Solvents

et al. 2008

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The effect of the size of gold particles deposited on CeO 2 and TiO 2 supports on their catalytic behavior in the aerobic oxidation of benzyl alcohol in different solvents (mesitylene, toluene, and supercritical carbon dioxide) has been investigated. The size of supported gold particles deposited via a colloidal route was in the range 1.3-11.3 nm, as determined by means of EXAFS and HAADF-STEM measurements. The catalytic performance of the supported gold catalysts in the different solvents revealed a significant effect of the gold particle size. Optimal activity was observed for catalysts with medium particle size (ca. 6.9 nm) whereas smaller and bigger particles showed inferior activity. Identical trends for the activity-particle size relationship were found using Au/CeO 2 and Au/TiO 2 for the reaction at atmospheric pressure in conventional solvents (mesitylene, toluene) as well as under supercritical conditions (scCO 2 ). Selectivity to benzaldehyde was only weakly affected by the gold particle size and mainly depended on reaction conditions. In supercritical CO 2 (scCO 2 ) selectivity was higher than in the conventional solvents under atmospheric pressure. All catalysts tested with particle sizes ranging from 1.3 to 11.3 nm showed excellent selectivity of 99% or higher under supercritical conditions.

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Section: Resultsmentioning

confidence: 99%

Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol: Effect of Gold Particle Size on Activity and Selectivity in Different Solvents

et al. 2008

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“…53 This was confirmed by CO adsorption on Au/TiO 2 , Au/ZrO 2 , and Au/FeO using infrared spectroscopy. 54,55 The CO oxidation involves adsorption of CO and O 2 ; the presence of lowcoordinated Au atoms was therefore regarded to be a key factor for the catalytic activity of Au nanoparticles. 19 However, a lower catalytic activity is found for monolayer Au (coordination number of 3-4) compared with bilayer Au (coordination number of ∼6 (see Figure 5b).…”

Section: Origins Of Exceptionally High Catalytic Activities For Nanosmentioning

confidence: 99%

Catalytically Active Gold: From Nanoparticles to Ultrathin Films

Chen

Goodman

2006

ChemInform

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Ordered gold (Au) mono-and bilayer structures have been synthesized on a highly reduced titania surface. The Au bilayer exhibits a significantly higher catalytic activity for carbon monoxide oxidation than does the Au monolayer structure. This is the first report of Au completely wetting an oxide surface and demonstrates that ultrathin Au films on an oxide surface have exceptionally high catalytic activity, comparable to the activity observed for Au nanoparticles. This discovery is a key to understanding the nature of the active site of supported Au catalysts.

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“…The first type of explanations associates the catalytic activity with the nature of the gold atoms in the particles. Both theory and experiments have pointed to the importance of lowcoordinated Au atoms acting as active sites [35][36][37][38][39][40][41][42][43][44][45][46][47]. A change in the electronic structure of gold, resulting in a metal-insulator transition has also been invoked [6,[48][49][50].…”

Section: Introductionmentioning

confidence: 99%

Insights into the reactivity of supported Au nanoparticles: combining theory and experiments

et al. 2007

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The origin of the extraordinary catalytic activity of gold nanoparticles is discussed on the basis of density-functional calculations, adsorption studies on single crystal surfaces, and activity measurements on well characterized supported gold particles. A number of factors are identified contributing to the activity, and it is suggested that it is useful to consider lowcoordinated Au atoms as the active sites, for example, CO oxidation and that the effect of the support can be viewed as structural and electronic promotion. We identify the adsorption energy of oxygen and the Au-support interface energy as important parameters determining the catalytic activity.

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Comparative Study of Au/TiO2 and Au/ZrO2 Catalysts for Low-Temperature CO Oxidation

Cited by 330 publications

References 39 publications

Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol: Effect of Gold Particle Size on Activity and Selectivity in Different Solvents

Gold-Catalyzed Aerobic Oxidation of Benzyl Alcohol: Effect of Gold Particle Size on Activity and Selectivity in Different Solvents

Catalytically Active Gold: From Nanoparticles to Ultrathin Films

Insights into the reactivity of supported Au nanoparticles: combining theory and experiments

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