New high-temperature superconductors based on oxides of thallium and copper, but not containing barium, have been prepared. A transition temperature ( T c ) about 85 K is found for (Tl 0.5 Pb Sr 2 CaCu O 7 whereas )Sr Ca Cu 3 9 has a 120 K. Both materials possess tetragonal symmetry with = 3.80 Å, 12.05 Å , 3.81 15.23 . structure refinement the latter phase carried out single-crystal x-ray diffraction data.

We present atomic and defect structural studies of technologically important gold nanorods synthesized by a wet chemical process. Our surface electron nanodiffraction from single have provided the first direct evidence stabilization highly unstable (110) surfactant molecules. The insights into structures implications in applications molecular device technology. origin development growth process been inferred results.

Abstract Gold nanoparticles offer the possibility of creating metamaterials; however, such are not particularly stable. Conversely, liquid crystals self‐organizing and self‐assembling materials, which can be designed to relatively Potentially, combining these two concepts could provide materials that induced assemble in a controlled way would have unique optical properties. This article describes some groundwork made preparation stable liquid‐crystalline metamaterials investigation their...

Understanding the oxidation and reduction mechanisms of catalytically active transition metal nanoparticles is important to improve their application in a variety chemical processes. In nanocatalysis can undergo or situ, thus redox species are not what observed before after reactions. We have used novel environmental scanning transmission electron microscope (ESTEM) with 0.1 nm resolution systematic studies complex dynamic copper nanoparticles. The has previously been reported be dependent...

A new mechanism for reactivity of multiply twinned gold nanoparticles resulting from their inherently strained structure provides a further explanation the surprising catalytic activity small nanoparticles. Atomic defect structural studies surface strains and quantitative analysis atomic column displacements in decahedral observed by aberration corrected transmission electron microscopy reveal an average expansion nearest neighbor distances 5.6%, with many more than 10%. Density functional...

High-resolution and in situ electron microscopy of vanadyl pyrophosphate catalysts reacted alkane (n-butane) other reducing environments have shown evidence for surface structure modifications accompanied by two sets symmetry-related extended defects. Defect analysis reveals that the defects are formed pure (glide) shear mechanism. The defect mechanism suggests presence basal (coplanar) anion vacancies, associated with Lewis acid centers, at oxygen sites linking corner-sharing phosphorus...

Twenty years ago, one of us embarked (Bursill, L. A.; Lodge, E. Thomas, J. M. Zeolitic structures as revealed by high-resolution electron microscopy. Nature 1980, 286, 111-113) on the study zeolites (renowned for their electron-beam sensitivity) transmission microscopy (HRTEM). In ensuing years, imaging aided optical diffractometry has yielded details open framework a number new aluminosilicate and aluminophosphate molecular sieves catalysts. The nature intergrowth recurrently twinned...

Techniques are presented for making ohmic contacts to nanowires with a thick oxide coating. Although experiments were carried out on Bi nanowires, the techniques described in this paper generally applicable other nanowire systems. Metal electrodes patterned individual using electron beam lithography. Imaging chemical reaction atomic scale situ high-resolution transmission microscopy shows that annealing H2 or NH3 can reduce nanowires' coating completely. The high temperatures required...

Abstract Advances in atomic resolution situ environmental transmission electron microscopy for direct probing of gas‐solid reactions, including at very high temperatures (∼2000°C) are described. In addition, recent developments dynamic real time studies the Angstrom level using a hot stage an aberration corrected environment presented. data from Pt/Pd nanoparticles on carbon with corresponding FFT/optical diffractogram illustrate achieved 0.11 nm 500°C and higher double TEM/STEM instrument...

We report atomic level high resolution transmission electron microscopy (HRTEM), nanodiffraction and nano-electron energy loss spectroscopy (nano-EELS) of boron-doped carbon nanostructures obtained by laser ablation Co/Ni/B-doped targets. The observations provide direct evidence for structural systematics defects as a function the B content in target. Targets with low concentration (below 3 at%), produced ropes single wall nanotubes (SWCNTs) no detectable boron present SWCNT ropes. However,...

Highly active and stable supported iron oxide nanoparticles show excellent activities switchable selectivities to target products in the microwave-assisted N-alkylation of amines with alcohols.

An efficient protocol for the hydrogenation of platform molecules (e.g.succinic acid) in aqueous environments using supported metal nanoparticles on polysaccharide derived mesoporous carbonaceous materials is reported first time.

ConspectusMany heterogeneous chemical reactions involve gases catalyzed over solid surfaces at elevated temperatures and play a critical role in the production of energy, healthcare, pollution control, industrial products, food. These catalytic take place atomic level, with active structures forming under reaction conditions. A fundamental understanding catalysis single atom resolution is therefore major advance rational framework upon which future processes can be built. Visualization...

Size-controlled MgO nanocrystals were synthesised via a simple sol-gel method and their bulk surface properties characterised by powder XRD, HRTEM XPS. Small, cubic single crystals, generated low temperature processing, expose weakly basic (100) surfaces. High annealing transforms these into large, stepped cuboidal nanoparticles of periclase which terminate in more (110) (111) The size dependent evolution electronic structure correlates directly with the associated catalytic activity towards...

A synergetic Fe-Al effect in Fe(2)O(3) nanoparticles supported on mesoporous aluminosilicates compared to pure siliceous silicates has been demonstrated, for the first time, by a remarkably superior catalytic activity of former microwave-assisted selective oxidation benzyl alcohol benzaldehyde. This significant finding, that also deeply influences acidity materials (increasing total and particularly Lewis acidity), can have important consequences improved efficiency these systems related...

Heterogeneous gas‐solid catalyst reactions occur on the atomic scale and there is increasing evidence single atoms very small clusters can act as primary active sites in chemical reactions. Aberration corrected environmental scanning transmission electron microscope (AC ESTEM) has been developed for novel studies of nanoparticle catalysts with Angstrom (0.1 nm) resolution gas. It extends high vacuum analyses full analytical facilities unrestricted angle annular dark field (HAADF) imaging...

We present the development of in situ wet environmental transmission electron microscopy (Wet-ETEM) for direct probing controlled liquid–catalyst reactions at operating temperatures on nanoscale. The first nanoscale imaging and diffraction dynamic liquid hydrogenation polymerization manufacture polyamides reported here opens up new opportunities high resolution studies a wide range solution–solid solution–gas–solid chemical biological sciences.

Evidence suggests that superconducting, orthorhombic YBa(2)Cu(3)O(6+x)+ (x greater, similar 0.5) is always produced by oxidation of the oxygen-deficient, tetragonal form less, this phase (commonly referred to as 123). A synthetic route whereby solution-derived, carbon-free precursors are decomposed at 650 degrees 700 C in inert atmosphere yield 123 now available. Appropriate include hydrated oxides derived from hydrolysis organometallic solutions and aqueous solution-derived hyponitrites....