Size-Dependent Stability of Supported Gold Nanostructures onto Ceria: an HRTEM Study

Majimel, Jérôme; Lamirand-Majimel, M.; Moog, Iona; Feral-Martin, Cédric; Tréguer‐Delapierre, Mona

doi:10.1021/jp9001115

Cited by 38 publications

(30 citation statements)

References 75 publications

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“…The values are close to the particle size of 4.0 nm determined for a 2 wt% Au supported on polyhedral ceria [14]. Most gold nanoparticles have a pyramidal or polyhedron shape, containing metallic atoms in the top layers and oxidic atoms in the interface [18,30,31]. The top layers appeared to be enclosed by {111} and {100} facets [31].…”

Section: Gold Species Stabilized On Rod and Cube Ceriasupporting

confidence: 80%

“…The formation of cationic Au δ+ on CeO 2 {111} films was kinetically limited and was attributed to the interaction of the gold adatoms with defects (oxygen vacancies) at low temperatures (∼100 K), which easily transformed into metallic at 300 K. In contrast, "cationic" Au species were formed in abundance on nano-CeO x and exhibited enhanced thermal stability. Majimel and co-workers [18] investigated the behavior of supported gold nanostructures with different sizes on the {111} surface of CeO 2 nanoparticles under the electron beam, where the high intensity of the electron beam induced formation of oxygen vacancies on the ceria surface. On a reduced ceria {111} surface, small-sized gold nanoparticles (<5 nm) shrunk layer by layer and migrated to the ceria surface, in which case a strong Au n -O-Ce interaction would be expected.…”

Section: Figurementioning

confidence: 99%

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Gold Clusters and Nanoparticles Stabilized by Nanoshaped Ceria in Catalysis

Guan

Song

Hensen

2015

Catalysis by Materials With Well-Defined Structures

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Section: Gold Species Stabilized On Rod and Cube Ceriasupporting

confidence: 80%

Section: Figurementioning

confidence: 99%

Gold Clusters and Nanoparticles Stabilized by Nanoshaped Ceria in Catalysis

Guan

Song

Hensen

2015

Catalysis by Materials With Well-Defined Structures

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“…First, most of the previous experiments were carried out by studying the catalysts before and after thermal treatment and reaction testing, but the details of any physical changes in the catalysts are not clear. Therefore, the sintering process should be observed by direct TEM imaging [279][280][281]. High-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) imaging should also be helpful to obtain images with higher resolution [282][283][284].…”

Section: Discussionmentioning

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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“…Most gold nanoparticles have a pyramidal shape. This has led others to propose that the atoms in the top layers of such particles are metallic, while those atoms that form the interface with the support are oxidic [44][45][46].…”

Section: Catalytic Activity Measurementsmentioning

confidence: 99%

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

et al. 2011

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The interaction of gold atoms with CeO 2 nanocrystals having rod and cube shapes has been examined by cyanide leaching, TEM, TPR, CO IR and X-ray absorption spectroscopy. After deposition-precipitation and calcination of gold, these surfaces contain gold nanoparticles in the range 2-6 nm. For the ceria nanorods, a substantial amount of gold is present as cations that replace Ce ions in the surface as follows from their first and second coordination shells of oxygen and cerium by EXAFS analysis. These cations are stable against cyanide leaching in contrast to gold nanoparticles. Upon reduction the isolated Au atoms form finely dispersed metal clusters with a high activity in CO oxidation, the WGS reaction and 1,3-butadiene hydrogenation. By analogy with the very low activity of reduced gold nanoparticles on ceria nanocubes exposing the {100} surface plane, it is inferred that the gold nanoparticles on the ceria nanorod surface also have a low activity in such reactions. Although the finely dispersed Au clusters are thermally stable up to quite high temperature in line with earlier findings (Y. Guan and E. J. M. Hensen, Phys Chem Chem Phys 11:9578, 2009), the presence of gold nanoparticles results in their more facile agglomeration, especially in the presence of water (e.g., WGS conditions). For liquid phase alcohol oxidation, metallic gold nanoparticles are the active sites. In the absence of a base, the O-H bond cleavage appears to be rate limiting, while this shifts to C-H bond activation after addition of NaOH. In the latter case, the gold nanoparticles on the surface of ceria nanocubes are much more active than those on the surface of nanorod ceria.

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Size-Dependent Stability of Supported Gold Nanostructures onto Ceria: an HRTEM Study

Cited by 38 publications

References 75 publications

Gold Clusters and Nanoparticles Stabilized by Nanoshaped Ceria in Catalysis

Gold Clusters and Nanoparticles Stabilized by Nanoshaped Ceria in Catalysis

Development of novel supported gold catalysts: A materials perspective

Gold Stabilized by Nanostructured Ceria Supports: Nature of the Active Sites and Catalytic Performance

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