English   español  
Por favor, use este identificador para citar o enlazar a este item: http://hdl.handle.net/10261/21587
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

The behavior of mixed-metal oxides: Physical and chemical properties of bulk Ce1–xTbxO2 and nanoparticles of Ce1–xTbxOy

AutorWang, Xianqin; Hanson, Jonathan C.; Liu, Gang; Rodríguez, José A.; Iglesias Juez, Ana ; Fernández García, Marcos
Palabras claveNanoparticles
Crystal defects
Vacancies (crystal)
Raman spectra
X-ray diffraction
Density functional theory
Fecha de publicación15-sep-2004
EditorAmerican Institute of Physics
CitaciónJournal of Chemical Physics 121(11): 5434 (2004)
ResumenThe physical and chemical properties of bulk Ce1–xTbxO2 and Ce1–xTbxOy nanoparticles (x<0.5) were investigated using synchrotron-based x-ray diffraction (XRD), x-ray adsorption near edge spectroscopy (XANES), Raman spectroscopy (RS), and first-principles density-functional (DF) calculations. DF results and Raman spectra point to a small tetragonal distortion after introducing terbium in ceria. The results of XRD show a small contraction ( <0.08 Å) in the cell dimensions. The presence of Tb generates strain in the lattice through the variation of the ionic radii and creation of crystal imperfections and O vacancies. The strain increases with the content of Tb and affects the chemical reactivity of the Ce1–xTbxOy nanoparticles towards hydrogen, SO2, and NO2. DF calculations for bulk Ce1–xTbxO2 and Ce8–nTbnO16 (n = 0, 1, 2, or 4) clusters show oxide systems that are not fully ionic. The theoretical results and XANES spectra indicate that neither a CeTb exchange nor the introduction of oxygen vacancies in Ce1–xTbxOy significantly affect the charge on the Ce cations. In contrast, the O K-edge and Tb LIII-edge XANES spectra for Ce1–xTbxOy nanoparticles show substantial changes with respect to the corresponding spectra of Ce and Tb single oxide references. The Ce0.5Tb0.5Oy compounds exhibit a much larger Tb3+/Tb4+ ratio than TbO1.7. A comparison with the properties of Ce1–xZrxOy and Ce1–xCaxOy shows important differences in the charge distribution, the magnitude of the dopant induced strain in the oxide lattice, and a superior behavior in the case of the Ce1–xTbxOy systems. The Tb-containing oxides combine stability at high temperature against phase segregation and a reasonable concentration of O vacancies, making them attractive for chemical and catalytic applications.
Descripción11 pages, 12 figures, 3 tables.-- PACS: 61.46.+w; 61.72.Ji; 78.70.Dm; 78.30.Hv; 71.15.Mb; 64.75.+g; 82.65.+r
Versión del editorhttp://dx.doi.org/10.1063/1.1781116
Aparece en las colecciones: (ICP) Artículos
Ficheros en este ítem:
Fichero Descripción Tamaño Formato  
GetPDFServlet.pdf511,85 kBAdobe PDFVista previa
Mostrar el registro completo

Artículos relacionados:

NOTA: Los ítems de Digital.CSIC están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.