Resolving the atomic structure of supported nanometer-size Au clusters

Lovall, D.; Buss, M.; Andres, R. P.; Reifenberger, R.

doi:10.1103/physrevb.58.15889

Cited by 16 publications

(11 citation statements)

References 27 publications

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“…In our simulations, the image spots are broadened by a Gaussian to approximate the finite resolution of the FIM operating at 100 K. This technique was used previously to successfully interpret field-ion images from nanometer-size Au clusters. 36 The FIM chamber is also equipped with an Omicron electron energy analyzer built on a cylindrical sector analyzer design having an entrance probe hole of 1 cm in diameter. The performance of the analyzer was tested by collecting and analyzing energy distributions from well-known field emitters like W͑110͒ in separate experiments.…”

Section: B Field Emission and Field-ion Microscopymentioning

confidence: 99%

Electron emission and structural characterization of a rope of single-walled carbon nanotubes

et al. 2000

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The electron emission and structural properties of an isolated ''rope'' comprised of ϳ70 individual singlewalled nanotubes ͑SWNT's͒ were investigated by measuring the field-emission energy distributions and by using field-ion microscopy ͑FIM͒. Field-emission energy distributions, obtained under ultrahigh-vacuum conditions, revealed that the emitting nanotube has a large density of states near the Fermi energy, with an energy distribution of emitted electrons close to that predicted by the free-electron theory. Two small features located on the trailing edge of the energy distributions are attributed to localized features in the density of states of a SWNT. FIM studies were also performed on the same rope in an attempt to provide structural information about the emitting nanotube. Initial FIM micrographs showed an uneven distribution of atoms. Eventually, rings of atoms were imaged. The atom placement around an individual ring structure is analyzed and found to be consistent with that expected from a single ͑19,13͒ SWNT.

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Section: B Field Emission and Field-ion Microscopymentioning

confidence: 99%

Electron emission and structural characterization of a rope of single-walled carbon nanotubes

et al. 2000

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“…Finally, three more applications are relevant for catalysis studies: the interaction of cyclohexane on Au tips [237], which finds its interest in the abatement of Volatile Organic Compounds (VOC); the behaviour of potassium-gold films [227], which could be used to study the influence of promoter in a catalytic reaction; and eventually, the imaging of Au nanoparticles by FIM after deposition on a field emitter tip [238,239], opening a way to study the catalytic process on a single Au nanoparticle rather than on a tip-model.…”

Section: Perspectivesmentioning

confidence: 99%

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

et al. 2017

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Abstract:Since the early discovery of the catalytic activity of gold at low temperature, there has been a growing interest in Au and Au-based catalysis for a new class of applications. The complexity of the catalysts currently used ranges from single crystal to 3D structured materials. To improve the efficiency of such catalysts, a better understanding of the catalytic process is required, from both the kinetic and material viewpoints. The understanding of such processes can be achieved using environmental imaging techniques allowing the observation of catalytic processes under reaction conditions, so as to study the systems in conditions as close as possible to industrial conditions. This review focuses on the description of catalytic processes occurring on Au-based catalysts with selected in situ imaging techniques, i.e., PEEM/LEEM, FIM/FEM and E-TEM, allowing a wide range of pressure and material complexity to be covered. These techniques, among others, are applied to unravel the presence of spatiotemporal behaviours, study mass transport and phase separation, determine activation energies of elementary steps, observe the morphological changes of supported nanoparticles, and finally correlate the surface composition with the catalytic reactivity.

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“…This might be achieved by the use of different pre-cursors. Attractive candidates are metal carbonyls (Fe(CO) 5 [27], Co 2 (CO) 8 [28], W(CO) 6 [29]) which tend to have purities around 85% after deposition. They decompose in an autocatalytic reaction, which may increase deposition efficiency in regions that the electron beam is not able to fully penetrate.…”

Section: Sample Preparation By Powder Lift-outmentioning

confidence: 99%

“…In order to access atomic scale structural information from nanoparticles, Lovall et al [6] used a field ion microscope, which is a high-field technique that is closely related to APT and uses field ionized gas atoms to image surfaces. They developed a setup capable of capturing single Au clusters from a metal cluster source in the size range up to 20 nm onto pre-sharpened tips, by detecting the resulting field electron emission.…”

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confidence: 99%

New approaches to nanoparticle sample fabrication for atom probe tomography

Felfer

Eder

et al. 2015

Ultramicroscopy

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Due to their unique properties, nano-sized materials such as nanoparticles and nanowires are receiving considerable attention. However, little data is available about their chemical makeup at the atomic scale, especially in three dimensions (3D). Atom probe tomography is able to answer many important questions about these materials if the challenge of producing a suitable sample can be overcome. In order to achieve this, the nanomaterial needs to be positioned within the end of a tip and fixed there so the sample possesses sufficient structural integrity for analysis. Here we provide a detailed description of various techniques that have been used to position nanoparticles on substrates for atom probe analysis. In some of the approaches, this is combined with deposition techniques to incorporate the particles into a solid matrix, and focused ion beam processing is then used to fabricate atom probe samples from this composite. Using these approaches, data has been achieved from 10-20 nm core-shell nanoparticles that were extracted directly from suspension (i.e. with no chemical modification) with a resolution of better than ± 1 nm.

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Resolving the atomic structure of supported nanometer-size Au clusters

Cited by 16 publications

References 27 publications

Electron emission and structural characterization of a rope of single-walled carbon nanotubes

Electron emission and structural characterization of a rope of single-walled carbon nanotubes

Dynamic Processes on Gold-Based Catalysts Followed by Environmental Microscopies

New approaches to nanoparticle sample fabrication for atom probe tomography

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