The role of the nano-environment of supported gold catalysts in the activity control. Modification of Au/Al2O3 catalysts by redox-type metal oxides

Szabó, Endre; Hegedűs, Mihály; Margitfalvi, József L.

doi:10.1007/s11144-008-5242-5

Cited by 5 publications

(3 citation statements)

References 15 publications

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“…Gold catalysts based on oxidemodified Al 2 O 3 supports include Au/MgO/Al 2 O 3 [189][190][191], Au/MnO x /Al 2 O 3 [192][193][194], Au/FeO x /Al 2 O 3 [192][193][194][195][196], Au/CoO x /Al 2 O 3 [192,194], Au/ZnO/Al 2 O 3 [192,197] [199], and Au/CeO 2 /Al 2 O 3 [200][201][202][203]. In particular, Nieuwenhuys and coworkers tested the performance of Al 2 O 3 -based gold catalysts in a number of reactions, and established that MgO/Al 2 O 3 [189], BaO/Al 2 O 3 [204,205], ZnO/Al 2 O 3 [197], and ZrO x /Al 2 O 3 [197] could all stabilize gold nanoparticles against thermal sintering.…”

Section: Pre-modification Of Al 2 O 3 Supportsmentioning

confidence: 99%

Development of novel supported gold catalysts: A materials perspective

2010

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Since Haruta et al. discovered that small gold nanoparticles finely dispersed on certain metal oxide supports can exhibit surprisingly high activity in CO oxidation below room temperature, heterogeneous catalysis by supported gold nanoparticles has attracted tremendous attention. The majority of publications deal with the preparation and characterization of conventional gold catalysts (e.g., Au/TiO 2 ), the use of gold catalysts in various catalytic reactions, as well as elucidation of the nature of the active sites and reaction mechanisms. In this overview, we highlight the development of novel supported gold catalysts from a materials perspective. Examples, mostly from those reported by our group, are given concerning the development of simple gold catalysts with single metal-support interfaces and heterostructured gold catalysts with complicated interfacial structures. Catalysts in the first category include active Au/SiO 2 and Au/metal phosphate catalysts, and those in the second category include catalysts prepared by pre-modification of supports before loading gold, by post-modification of supported gold catalysts, or by simultaneous dispersion of gold and an inorganic component onto a support. CO oxidation has generally been employed as a probe reaction to screen the activities of these catalysts. These novel gold catalysts not only provide possibilities for applied catalysis, but also furnish grounds for fundamental research.

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Section: Pre-modification Of Al 2 O 3 Supportsmentioning

confidence: 99%

Development of novel supported gold catalysts: A materials perspective

2010

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“…Many supports have been used so far, including doped aluminas (Grisel et al 2000(Grisel et al , 2001(Grisel et al , 2002aGrisel and Nieuwenhuys 2001a, b;Gluhoi et al 2003Gluhoi et al , 2004Lin et al 2004;Szabo et al 2005Szabo et al , 2007Szabo et al , 2008Szabo et al , 2009Gluhoi et al 2005a, b;2006a, b;Gluhoi and Nieuwenhuys 2007a, b;Lippits et al 2007Lippits et al , 2008Lippits et al , 2009Tornpos et al 2008Tornpos et al , 2010. Detailed studies on the effects of addition of (earth) alkali metals to Au/c-Al 2 O 3 catalysts, reveal that the (earth) alkali metal oxide MO x (where M is the metal) acts as structural promoter, stabilizing the Au nanoparticles, preventing them from sintering under mild conditions; and facilitating the O 2 activation, Electronic supplementary material The online version of this article (doi:10.1007/s13204-011-0037-9) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

“…Most doped aluminas described in literature were obtained by impregnation of a metal oxide precursor solution into the alumina support, followed by calcination between 350 and 450°C (Grisel et al 2000(Grisel et al , 2001(Grisel et al , 2002aGrisel and Nieuwenhuys 2001a, b ;Gluhoi et al 2004Gluhoi et al , 2005aGluhoi et al , 2006bLin et al 2004;Szabo et al 2005Szabo et al , 2007Szabo et al , 2008Szabo et al , 2009Gluhoi and Nieuwenhuys 2007a, b ;Lippits et al 2007Lippits et al , 2008Lippits et al , 2009Tornpos et al 2008Tornpos et al , 2010, and were prepared using a metal/Al ratio of 1:15 (Gluhoi et al 2005a). Since this procedure is quite lengthy, involves a calcination step, and the results obtained are aluminas doped with metal oxides, we decided to compare the results obtained with the ''classical'' doping method of impregnation and calcination (IC) with those obtained by a simpler method: directly adding the metal oxide to the alumina support by physical mixture (PM), and test both types of materials for CO oxidation, before and after gold addition.…”

Section: Introductionmentioning

confidence: 99%

Gold on oxide-doped alumina supports as catalysts for CO oxidation

2011

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The effect of doping a commercial alumina support with metal oxides of Ce, Co, Cu, Fe, La, Mg, Mn, Ni and Zn was investigated. Doped d-Al 2 O 3 samples were obtained by simple physical mixture (PM) of the alumina with the desired commercial oxide and by traditional impregnation of alumina with precursor salts of the same metals followed by calcination (IC). The metal load (7% wt.) was the same in both cases. Gold (1% wt.) was loaded using a liquid phase reductive deposition method. The obtained materials were characterized by adsorption of N 2 at -196°C, temperature programmed reduction, X-ray diffraction, energy-dispersive X-ray spectrometry and transmission electron microscopy. Both samples prepared by PM and IC showed a mixture of the d-alumina phase with the respective metal oxide, but the BET surface areas of the IC samples were, in general, higher than those of the PM materials. The particle size of the oxide phases were larger for the PM samples than for the IC materials. Nevertheless, catalytic experiments for CO oxidation showed that PM samples were much more active than IC. That could be explained by the size of gold nanoparticles, well known to be related with catalytic activity, that was lower in samples prepared by PM (7-16 nm) than by IC (11-17 nm). Gold was found to be in the metallic state. The most active samples were aluminas containing Zn and Fe prepared by PM that had the smallest gold nanoparticles sizes (7-13 and 8-12 nm, respectively) and had room temperature activities for CO conversion of 0.62 and 1.34 mol CO h -1 g Au -1 , respectively, which are larger than those found in the literature for doped c-alumina samples.

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