560 research outputs found
Report drawn up on behalf of the Committee on Energy, Research and Technology on the proposal from the Commission of the European Communities to the Council (Doc. 237/73) for a decision adopting provisions for the dissemination of information relating to research programmes for the European. Economic Community. EP Working Document, Document 1973-1974 355/73, 11 February 1974
On the role of the gas environment, electron-dose-rate, and sample on the image resolution in transmission electron microscopy
Visualizing atomic-scale redox dynamics in vanadium oxide-based catalysts
Surface redox processes involving oxygen atom exchange are fundamental in catalytic
reactions mediated by metal oxides. These processes are often difficult to uncover
due to changes in the surface stoichiometry and atomic arrangement. Here we employ
high-resolution transmission electron microscopy to study vanadium oxide supported
on titanium dioxide, which is of relevance as a catalyst in, e.g., nitrogen oxide emission
abatement for environmental protection. The observations reveal a reversible transformation
of the vanadium oxide surface between an ordered and disordered state, concomitant with a
reversible change in the vanadium oxidation state, when alternating between oxidizing and
reducing conditions. The transformation depends on the anatase titanium dioxide surface
termination and the vanadium oxide layer thickness, suggesting that the properties of
vanadium oxide are sensitive to the supporting oxide. These atomic-resolution observations
offer a basis for rationalizing previous reports on shape-sensitive catalytic properties
The application of inelastic neutron scattering to investigate the ‘dry’ reforming of methane over an alumina-supported nickel catalyst operating under conditions where filamentous carbon formation is prevalent
The use of CO2 in reforming methane to produce the industrial feedstock syngas is an economically and environmentally attractive reaction. An alumina-supported nickel catalyst active for this reaction additionally forms filamentous carbon. The catalyst is investigated by inelastic neutron scattering as well as elemental analysis, temperature-programmed oxidation, temperature-programmed hydrogenation, X-ray diffraction, transmission electron microscopy and Raman scattering. Isotopic substitution experiments, using 13CO2 for 12CO2, show the oxidant to contribute to the carbon retention evident with this sample. At steady-state operation, a carbon mass balance of 95 % is observed. A kinetic scheme is proposed to account for the trends observed
Mechanisms for catalytic carbon nanofiber growth studied by ab initio density functional theory calculations
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