Journal ArticleDOI
Atom-Resolved Imaging of Dynamic Shape Changes in Supported Copper Nanocrystals
Poul L. Hansen,Jakob Birkedal Wagner,Stig Helveg,Jens R. Rostrup-Nielsen,Bjerne S. Clausen,Henrik Topsøe +5 more
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TLDR
In situ transmission electron microscopy is used to obtain atom-resolved images of copper nanocrystals on different supports, which are catalysts for methanol synthesis and hydrocarbon conversion processes for fuel cells.Abstract:
In situ transmission electron microscopy is used to obtain atom-resolved images of copper nanocrystals on different supports. These are catalysts for methanol synthesis and hydrocarbon conversion processes for fuel cells. The nanocrystals undergo dynamic reversible shape changes in response to changes in the gaseous environment. For zinc oxide-supported samples, the changes are caused both by adsorbate-induced changes in surface energies and by changes in the interfacial energy. For copper nanocrystals supported on silica, the support has negligible influence on the structure. Nanoparticle dynamics must be included in the description of catalytic and other properties of nanomaterials. In situ microscopy offers possibilities for obtaining the relevant atomic-scale insight.read more
Citations
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Journal ArticleDOI
The Role of Gas in Determining Image Quality and Resolution During In Situ Scanning Transmission Electron Microscopy Experiments
TL;DR: In this article, the effects of different gases at various pressures on the quality and resolution of images obtained at room temperature in the annular dark field STEM imaging mode using a differentially pumped (DP) gas cell.
Book ChapterDOI
7.06 – Monolayer Systems
I.E. Wachs,C.J. Keturakis +1 more
TL;DR: In situ and operando spectroscopy characterization of monolayer metal oxide catalysts can be used to investigate catalytic molecular/electronic structure-activity/selectivity relationships for chemical reactions.
Journal ArticleDOI
Illuminating surface atoms in nanoclusters by differential X-ray absorption spectroscopy
Charles S. Spanjers,Thomas P. Senftle,Adri C. T. van Duin,Michael J. Janik,Anatoly I. Frenkel,Robert M. Rioux +5 more
TL;DR: Together, experiment and theory highlight the ability of Δ-EXAFS to probe surface atoms of Pd nanoclusters and suggest that under-coordinated atoms are trapped in metastable states at 77 K and Ar provides the kinetic energy needed to overcome the barrier for surface restructuring.
Journal ArticleDOI
Catalytic activity of copper oxide/zinc oxide composites prepared by thermolysis of crystallographically defined bimetallic coordination compounds
Rainer Weiss,Yanzhi Guo,Sascha Vukojević,Lamma Khodeir,Roland Boese,Ferdi Schüth,Martin Muhler,Matthias Epple +7 more
TL;DR: In this article, the suitability of bimetallic coordination compounds in the systems Cu/Zn/CN and Zn[Cu(CN)3] as precursors for the formation of methanol from synthesis gas was explored.
Journal ArticleDOI
Progress in environmental high-voltage transmission electron microscopy for nanomaterials
Nobuo Tanaka,Takeshi Fujita,Yoshimasa Takahashi,Jun Yamasaki,Jun Yamasaki,Kazuyoshi Murata,Shigeo Arai +6 more
TL;DR: The detailed design of the E-HVEM, recent developments and various applications are described, including the application of high-voltage transmission electron microscopy to environmental observations in the gas atmosphere because of high transmission of electrons through gas layers and thick samples.
References
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Journal ArticleDOI
Controlled growth of monodisperse silica spheres in the micron size range
TL;DR: In this article, a system of chemical reactions has been developed which permits the controlled growth of spherical silica particles of uniform size by means of hydrolysis of alkyl silicates and subsequent condensation of silicic acid in alcoholic solutions.
Journal ArticleDOI
Semiconductor Clusters, Nanocrystals, and Quantum Dots
TL;DR: In this article, the authors focus on the properties of quantum dots and their ability to join the dots into complex assemblies creates many opportunities for scientific discovery, such as the ability of joining the dots to complex assemblies.
Reference BookDOI
Handbook of Heterogeneous Catalysis
TL;DR: This paper presents a meta-modelling system that automates the very labor-intensive and therefore time-heavy and therefore expensive and expensive process of characterization and activation of Solid Catalysts.
Journal ArticleDOI
Photoinduced conversion of silver nanospheres to nanoprisms.
TL;DR: This light-driven process results in a colloid with distinctive optical properties that directly relate to the nanoprism shape of the particles, which could be useful in developing multicolor diagnostic labels on the basis of nanoparticle composition and size but also of shape.
Journal ArticleDOI
Some interesting properties of metals confined in time and nanometer space of different shapes.
TL;DR: Some of the observed new chemical, optical, and thermal properties of metallic nanocrystals when their size is confined to the nanometer length scale and their dynamical processes are observed on the femto- to picosecond time scale are described.