The methane reforming reaction with carbon dioxide as the oxidant over alumina-supported nickel and gold-doped nickel catalysts is studied using a variety of techniques such as reaction testing, vibrational spectroscopy (inelastic neutron scattering (INS), Raman scattering and infrared absorption), temperature-programmed oxidation (TPO), transmission electron microscopy and X-ray powder diffraction. The quantities of retained carbon and hydrogen are determined by TPO and INS, respectively. Minimal hydrogen retention indicates these catalysts to be very efficient at cycling hydrogen. The relative partitioning of hydrogen within the reaction media is used to formulate a qualitative description of the reaction kinetics. The presence of the gold modifier does not appear to provide any improvement in catalyst performance under the specified reaction conditions.
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http://dx.doi.org/10.1039/c2cp42745a | DOI Listing |
Nat Mater
January 2025
School of Physics, Zhejiang University, Hangzhou, China.
In ordered magnets, the elementary excitations are spin waves (magnons), which obey Bose-Einstein statistics. Similarly to Cooper pairs in superconductors, magnons can be paired into bound states under attractive interactions. The Zeeman coupling to a magnetic field is able to tune the particle density through a quantum critical point, beyond which a 'hidden order' is predicted to exist.
View Article and Find Full Text PDFSci Bull (Beijing)
January 2025
Department of Chemistry, University of Manchester, Manchester, M13 9PL, UK; College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China. Electronic address:
The methanol-to-olefins (MTO) process has the potential to bridge future gaps in the supply of sustainable lower olefins. Promoting the selectivity of propylene and ethylene and revealing the catalytic role of active sites are challenging goals in MTO reactions. Here, we report a novel heteroatomic silicoaluminophosphate (SAPO) zeolite, SAPO-34-Ta, which incorporates active tantalum(V) sites within the framework to afford an optimal distribution of acidity.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Neutron Sciences Directorate, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA.
Advanced batteries require advanced characterization techniques, and neutron scattering is one of the most powerful experimental methods available for studying next-generation battery materials. Neutron scattering offers a non-destructive method to probe the complex structural and chemical processes occurring in batteries during operation in truly in situ/in operando measurements with a high sensitivity to battery-relevant elements such as lithium. Neutrons have energies comparable to the energies of excitations in materials and wavelengths comparable to atomic distances in the solid state, thus giving access to study structural and dynamical properties of materials on an atomic scale.
View Article and Find Full Text PDFNPJ Quantum Mater
January 2025
NIST Center for Neutron Research, Gaithersburg, MD 20899 USA.
The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry and points and disperse along the crystallographic -axis. In applied magnetic fields to at least = 11 T along the , the magnetism is found to be field-independent in the ( 0) plane.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Laboratory for Quantum Magnetism, Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Quantum magnetic materials can provide explicit realizations of paradigm models in quantum many-body physics. In this context, SrCu_{2}(BO_{3})_{2} is a faithful realization of the Shastry-Sutherland model for ideally frustrated spin dimers, even displaying several of its quantum magnetic phases as a function of pressure. We perform inelastic neutron scattering measurements on SrCu_{2}(BO_{3})_{2} at 5.
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