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Your search keyword '"Giamello, E"' showing total 18 results
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18 results on '"Giamello, E"'

16. The O-17 hyperfine structure of trapped holes photo generated at the surface of polycrystalline MgO

Author

Chiesa, M, Giamello, E, DI VALENTIN, C, Pacchioni, G, CHIESA, MASSIMO, DI VALENTIN, CRISTIANA, PACCHIONI, GIANFRANCO, Chiesa, M, Giamello, E, DI VALENTIN, C, Pacchioni, G, CHIESA, MASSIMO, DI VALENTIN, CRISTIANA, and PACCHIONI, GIANFRANCO

Abstract

Surface trapped hole centers have been generated by X-ray irradiation on an O-17 isotope enriched MgO sample. The resulting EPR spectrum allowed us to determine for the first time the complete O-17(-) hyperfine tensor (A = {[18.6, 18.6, -104.8] G). Comparison of the measured data with those obtained by embedded cluster density functional theory calculations allows to identify the hole trapping center with three-coordinated oxide anions localized at MgO corners. (C) 2005 Elsevier B.V. All rights reserved.}

Published
2005

17. EPR approaches to heterogeneous catalysis. The chemistry of titanium in heterogeneous catalysts and photocatalysts.

Author

Morra E, Giamello E, and Chiesa M

Abstract

Paramagnetic species are often involved in catalytic or photocatalytic reactions occurring at the solid-gas interface of heterogeneous catalysts. In this contribution we will provide an overview of the wealth and breadth of information that can be obtained from EPR in the characterization of paramagnetic species in such systems, illustrating the advantages that modern pulsed EPR methodologies can offer in monitoring the elementary processes occurring within the coordination sphere of surface transition-metal ions. To do so we selected three representative systems, where titanium ions in low oxidation states act as active catalytic sites, trying to outline the methodological approaches which characterize the application of EPR techniques and the questions that can be answered and addressed relative to the characterization of heterogeneous catalytic materials., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Published
2017
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18. An ESR study of titanium-silicalite in presence of H2O2.

Author

Bonoldi L, Busetto C, Congiu A, Marra G, Ranghino G, Salvalaggio M, Spanò G, and Giamello E

Subjects
Anions, Chemical Phenomena, Chemistry, Physical, Models, Chemical, Oxygen, Silicates analysis, Temperature, Titanium analysis, Ultraviolet Rays, Electron Spin Resonance Spectroscopy methods, Hydrogen Peroxide chemistry, Silicates chemistry, Titanium chemistry
Abstract

The interaction of H2O2 with TS-1 has been investigated by the ESR technique. A well manufactured TS-1 has been considered, where the presence of extra-structural titanium can be excluded. The two main signals observed are attributed to oxygen radical species co-ordinated on structural titanium sites, and the relevant effect of water presence in the paramagnetic complex is discussed. A comparison is performed with O2-/Ti species in TS-1 obtained by reduction/re-oxidation procedures of Ti(IV). Moreover, some possible structural configurations of the paramagnetic sites are proposed, for two of which ab initio calculation yield g(z)-values quite close to the experimental ones.

Published
2002
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