Atom-Resolved Imaging of Dynamic Shape Changes in Supported Copper Nanocrystals

• Published in: Science (American Association for the Advancement of Science) Vol. 295; no. 5562; pp. 2053 - 2055
• Main Authors: Hansen, Poul L., Wagner, Jakob B., Helveg, Stig, Rostrup-Nielsen, Jens R., Clausen, Bjerne S., Topsøe, Henrik
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 15.03.2002; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Applied sciences; Atoms & subatomic particles; Catalysis; Catalysts: preparations and properties; Chemistry; Climate; Clusters, nanoparticles, and nanocrystalline materials; Condensed matter: structure, mechanical and thermal properties; Copper; Cross-disciplinary physics: materials science; rheology; Crystallography; Crystals; Electron microscopy; Exact sciences and technology; Free energy; General and physical chemistry; Hydrogen; Imaging; Materials science; Metals. Metallurgy; Molecular electronics; Nanocrystals; Nanoparticles; Nanoscale materials and structures: fabrication and characterization; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Nanotechnology; Physics; Quantum statistics; Silica; Structure of solids and liquids; crystallography; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Vibration mode; Denmark; Morphological changes; Reversible processes; Catalysts; In situ; Experimental study; High-resolution methods; Substrates; Nanoparticles; Transmission electron microscopy; Dynamics; Transition elements; Imaging; Copper; Crystal morphology; Nanocrystal
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1069325

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.