Aberration-Corrected Electron Microscopy of Nanoparticles

Yacamán, Miguel José; Santiago, Ulises; Mejía-Rosales, Sergio

doi:10.1007/978-3-319-15177-9_1

Cited by 3 publications

(2 citation statements)

References 39 publications

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“…However, the intensity in HAADF images is not a linear function of the number of atoms in the atomic columns, having a stepped behavior which originates uncertainty of the 3D shape. 35 More detailed information on the actual shape of the evaporated particles was obtained by implementing the off-axis electron holography technique. In electron holography, unlike electron diffraction, the phase of the exit electron wave can be recovered.…”

Section: Resultsmentioning

confidence: 99%

Evaporation of Gold on NaCl Surfaces as a Way To Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Mendoza‐Cruz

Romeu

Bazán-Díaz

et al. 2017

Crystal Growth & Design

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Herein, the growth of Au nanoparticles on NaCl surfaces as a way to control their spatial distribution is explored, giving new insights into the shape and relative orientation of the resulting nanoparticles through modern electron microscopy techniques. Their morphological features depending on the geometry of the NaCl surface site they nucleated on are described in detail. Also, hitherto unreported small but systematic angular deviations in the range of 1–4° from the exact epitaxial orientation were observed. A theoretical approach based on straightforward elastic energy considerations and yet capable of accounting for the experimental results was developed. The production of metallic nanoparticles is a fundamental subject in the development of nanotechnology, and the fine control of the shape and spatial distribution is an important issue for the applicability of nanoparticles. Furthermore, in spite of the extensive research on this topic, some key features such as the precise mechanism controlling particle shape and particle-substrate orientation are still not well understood as evidenced by the results of this work. Thus, a clear understanding of the role played by the diverse factors involved in epitaxial growth is required to produce nanoparticles with finely tailored properties.

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Section: Resultsmentioning

confidence: 99%

Evaporation of Gold on NaCl Surfaces as a Way To Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Mendoza‐Cruz

Romeu

Bazán-Díaz

et al. 2017

Crystal Growth & Design

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“…Due to its high lateral resolution and chemical sensitive z-contrast imaging technique [high angle annular dark field (HAADF)] Cs-corrected electron microscopy is recognized as a perfect tool to study localized morphological, structural, and compositional changes of Pt or other heavy metal element-based nanoparticles. , Direct observation and tracking of these changes, usually connected to the electrocatalyst degradation, are possible with the advanced characterization method named identical location transmission electron microscopy (IL-TEM). − It enables tracking of morphological surface changes on a nanometer scale on identical locations of an electrocatalyst material before and after electrochemical aging. Compared to usual imaging of random parts of material with certain statistical uncertainty, it provides direct proof of the studied events.…”

Section: Introductionmentioning

confidence: 99%

Atomic Scale Insights into Electrochemical Dissolution of Janus Pt–SnO₂ Nanoparticles in the Presence of Ethanol in Acidic Media: An IL-STEM and EFC–ICP–MS Study

et al. 2018

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The studies on Pt-or Pt alloy-based catalysts for ethanol oxidation have been focused mostly on their activity, with much less emphasis on their stability. Dissolution of commercial Pt−SnO 2 /C electrocatalyst for direct ethanol fuel cells was investigated on the atomic scale by employing two advanced electrochemical characterization techniques: (i) identical location scanning transmission electron microscopy (IL-STEM) and (ii) electrochemical flow cell connected to inductively coupled mass spectrometry (EFC−ICP−MS). IL-STEM provides electrochemically induced atomic scale insights into morphological and structural changes of Pt−SnO 2 /C Janus type nanoparticles, and the second methodological configuration enables potential-and timeresolved dissolution monitoring of individual metal counterparts with extremely high sensitivity, even in the presence of ethanol. We observe that Sn is mostly dissolving in the anodic potential ramp, which is, as a rule, not affected by the presence of ethanol. Surprisingly, Pt dissolution gets dramatically enhanced in the presence of ethanol with the onset already at 0.57 V. Compared to the experiment without ethanol, the onset is at 1.1 V, which is typical for Pt. We discuss the possible mechanisms governing these alterations.

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Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

et al. 2016

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Single metal atoms and metal clusters have attracted much attention thanks to their advantageous capabilities as heterogeneous catalysts. However, the generation of stable single atoms and clusters on a solid support is still challenging. Herein, we report a new strategy for the generation of single Pt atoms and Pt clusters with exceptionally high thermal stability, formed within purely siliceous MCM-22 during the growth of a two-dimensional zeolite into three dimensions. These subnanometric Pt species are stabilized by MCM-22, even after treatment in air up to 540 °C. Furthermore, these stable Pt species confined within internal framework cavities show size-selective catalysis for the hydrogenation of alkenes. High-temperature oxidation-reduction treatments result in the growth of encapsulated Pt species to small nanoparticles in the approximate size range of 1 to 2 nm. The stability and catalytic activity of encapsulated Pt species is also reflected in the dehydrogenation of propane to propylene.

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Aberration-Corrected Electron Microscopy of Nanoparticles

Cited by 3 publications

References 39 publications

Evaporation of Gold on NaCl Surfaces as a Way To Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Evaporation of Gold on NaCl Surfaces as a Way To Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Atomic Scale Insights into Electrochemical Dissolution of Janus Pt–SnO₂ Nanoparticles in the Presence of Ethanol in Acidic Media: An IL-STEM and EFC–ICP–MS Study

Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

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Aberration-Corrected Electron Microscopy of Nanoparticles

Cited by 3 publications

References 39 publications

Evaporation of Gold on NaCl Surfaces as a Way To Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Evaporation of Gold on NaCl Surfaces as a Way To Control Spatial Distribution of Nanoparticles: Insights on the Shape and Crystallographic Orientation

Atomic Scale Insights into Electrochemical Dissolution of Janus Pt–SnO2 Nanoparticles in the Presence of Ethanol in Acidic Media: An IL-STEM and EFC–ICP–MS Study

Generation of subnanometric platinum with high stability during transformation of a 2D zeolite into 3D

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Atomic Scale Insights into Electrochemical Dissolution of Janus Pt–SnO₂ Nanoparticles in the Presence of Ethanol in Acidic Media: An IL-STEM and EFC–ICP–MS Study