Modeling the Structure and Composition of Nanoparticles by Extended X-Ray Absorption Fine-Structure Spectroscopy

Frenkel, Anatoly I.; Yevick, Aaron; Cooper, Chana; Vasić, Relja

doi:10.1146/annurev-anchem-061010-113906

Cited by 164 publications

(175 citation statements)

References 66 publications

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“…The reduction in intensity of the NPG can be caused by either the reduced coordination number compared to the bulk, the increased bond length disorder or both. Although it is possible to separately evaluate these two effects in nanoparticles, where the coordination numbers are much smaller than in their bulk counterparts, [36][37][38] in the case of the NPG the discrimination between these two contributions at the single temperature is complicated. Obtaining this information from EXAFS is much easier by utilizing strong temperature dependence of EXAFS amplitude and phase (Fig.…”

Section: Resultsmentioning

confidence: 99%

Thermal properties of nanoporous gold

et al. 2012

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We measured the thermal expansion coefficient and Debye temperature of nanoporous gold (NPG) using Extended X-ray Absorption Fine Structure technique. Reduction of the nearest neighbor distances in NPG by ca. 0.01 Å compared to the bulk gold was attributed to the surface tension caused, in turn, by the finite size effect of the NPG ligaments. We also obtained that the Debye temperature in NPG is 5% lower than in bulk gold. We interpreted these observations in the framework of a bimodal distribution of surface and bulk bonds with different values of Debye temperature. The surface bonds with low Debye temperature extend within ca. 4 layers of Au atoms located on the pore surface, in a good agreement with prior resistivity measurements and theoretical predictions. 63.22.Dc, 61.05.cj, 65.40.De, PACS number(s):

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Section: Resultsmentioning

confidence: 99%

Thermal properties of nanoporous gold

et al. 2012

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“…The XANES and extended X-ray absorption fine structure (EXAFS) data processing and analysis were performed using the IFEFFIT package 32 . The EXAFS data modelling and analysis were performed using standard procedures [32][33][34][35][36] .…”

Section: Methodsmentioning

confidence: 99%

Catalysis on singly dispersed bimetallic sites

et al. 2015

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A catalytic site typically consists of one or more atoms of a catalyst surface that arrange into a configuration offering a specific electronic structure for adsorbing or dissociating reactant molecules. The catalytic activity of adjacent bimetallic sites of metallic nanoparticles has been studied previously. An isolated bimetallic site supported on a non-metallic surface could exhibit a distinctly different catalytic performance owing to the cationic state of the singly dispersed bimetallic site and the minimized choices of binding configurations of a reactant molecule compared with continuously packed bimetallic sites. Here we report that isolated Rh 1 Co 3 bimetallic sites exhibit a distinctly different catalytic performance in reduction of nitric oxide with carbon monoxide at low temperature, resulting from strong adsorption of two nitric oxide molecules and a nitrous oxide intermediate on Rh 1 Co 3 sites and following a low-barrier pathway dissociation to dinitrogen and an oxygen atom. This observation suggests a method to develop catalysts with high selectivity.

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“…As the EXAFS signal is averaged over all absorbing atoms, larger Au NPs will not see such a dramatic change in Au-Au coordination with a small change in composition due to the higher amount of atoms in the core versus on the surface. A comprehensive review on the geometrical and compositional characterization of NPs from EXAFS can be found by Frenkel et al [42].…”

Section: Introduction To Gold Nanoclustersmentioning

confidence: 99%

Bonding properties of thiolate-protected gold nanoclusters and structural analogs from X-ray absorption spectroscopy

Chevrier

Yang

Chatt

et al. 2015

Nanotechnology Reviews

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Abstract:Subnanometer, atomically precise thiolateprotected gold nanoclusters represent an important advancement in our understanding of thiolate-protected gold nanoparticles and thiolate-gold chemistry. Aside from being a link between larger gold nanoparticles and small gold complexes, gold nanoclusters exhibit extraordinary molecule-like optical, electronic, and physicochemical properties that are promising for next-generation imaging agents, sensing devices, or catalysts. The success in elucidating a number of unique thiolate-gold surface and gold core structures has greatly improved our understanding of thiolate-gold nanoclusters. Nevertheless, monitoring the structural and electronic behavior of thiolate-protected gold nanoclusters in a variety of media or environments is crucial for the next step in advancing this class of nanomaterials. Not to mention, there are a number of thiolateprotected gold nanoclusters with unknown structures or compositions that could reveal important insights on application-based properties such as luminescence or catalytic activity. This review summarizes some of the recent contributions from X-ray absorption spectroscopy (XAS) studies on the intriguing bonding properties of thiolate-protected gold nanoclusters and some structural analogs. Advantages from XAS include a local structural, site-and elementspecific analysis, suitable for ultra-small particle sizes (1-2 nm), along with versatile experimental conditions.

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Modeling the Structure and Composition of Nanoparticles by Extended X-Ray Absorption Fine-Structure Spectroscopy

Cited by 164 publications

References 66 publications

Thermal properties of nanoporous gold

Thermal properties of nanoporous gold

Catalysis on singly dispersed bimetallic sites

Bonding properties of thiolate-protected gold nanoclusters and structural analogs from X-ray absorption spectroscopy

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