NMR and Mössbauer Study of Al2O3–Eu2O3 |
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Authors: | N. Nava P. Salas M. E. Llanos H. Pérez-Pastenes T. Viveros |
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Affiliation: | (1) Instituto Mexicano del Petróleo, Programa de Ingeniería Molecular, Eje Central Lázaro Cárdenas No. 152, Col Atepehuacan, C.P. 07730, México D. F.;(2) Departamento de IPH, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, C.P. 09340, México D. F |
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Abstract: | Alumina–europia mixed oxides with 5 and 10 wt.% Eu2O3 were studied by Mössbauer spectroscopy, 27Al MAS-NMR and X-ray diffraction (XRD). The samples were prepared by the sol–gel technique. The XRD patterns for the calcined samples show a broad peak around 2θ = 30° which is assigned to the Eu2O3; after treatment with hydrogen at 1073 K no reduction to Eu+2 or Eu0 was observed. The NMR spectra show three peaks, which are assigned to the octahedral, pentahedral and tetrahedral aluminum sites; the intensity of each peak depends on the concentration of europium ions. The Mössbauer spectra of the calcined samples show a single peak near zero velocity which is attributed to the Eu+3; after H2 treatment at 1073 K similar spectra were obtained, suggesting Eu+3 is not reducibly at this temperature. |
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Keywords: | M?ssbauer spectroscopy nuclear magnetic resonance X-ray diffraction |
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