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
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Dynamic observations of Au catalysts by environmental electron microscopy
TL;DR: Au clusters in the size range (1-8 nm), supported on MgO and TiO2, are studied at the atomic scale by High Resolution Transmission Electron Microscopy (HRTEM), in standard conditions and during cycles of gas treatments by environmental HRTEM as mentioned in this paper.
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Dynamic interplay between metal nanoparticles and oxide support under redox conditions
TL;DR: Frey et al. as discussed by the authors showed that the strong metal-support interaction (SMSI)-induced encapsulation of platinum particles on titania observed under reducing conditions is lost once the system is exposed to a redox-reactive environment containing oxygen and hydrogen at a total pressure of ~1 bar.
Journal ArticleDOI
Mechanisms of Copper-Based Catalyst Deactivation during CO2 Reduction to Methanol
TL;DR: In this paper, it was shown that different gaseous species impact catalytic reactions in the methanol synthesis process, despite the fact that the synthesis process includes industrially some of the most important catalytic chemical reactions.
Journal ArticleDOI
Revealing correlation of valence state with nanoporous structure in cobalt catalyst nanoparticles by in situ environmental TEM
TL;DR: In this paper, an environmental transmission electron microscope equipped with a differentially pumped gas cell was used to conduct nanoscopic imaging and electron energy loss spectroscopy in situ for cobalt catalysts under reaction conditions.
Journal ArticleDOI
Insights into the physical chemistry of materials from advances in HAADF-STEM
TL;DR: How advances in STEM, often coupled with first-principles theory, have led to interesting and important new insights into the physical chemistry of materials are reviewed.
References
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