The structure evolution in the CeO2-Sm2O3system is revisited by combining high resolution synchrotron powder diffraction with pair distribution function (PDF) to inquire about local, mesoscopic, and average structure. The CeO2fluorite structure undergoes two phase transformations by Sm doping, first to a cubic (C-type) and then to a monoclinic (B-type) phase. Whereas the C to B-phase separation occurs completely and on a long-range scale, no miscibility gap is detected between fluorite and C-type phases. The transformation rather occurs by growth of C-type nanodomains embedded in the fluorite matrix, without any long-range phase separation. A side effect of this mechanism is the ordering of the oxygen vacancies, which is detrimental for the application of doped ceria as an electrolyte in fuel cells. The results are discussed in the framework of other Y and Gd dopants, and the relationship between nanostructuring and the above equilibria is also investigated.

Phase Transformations in the CeO2-Sm2O3System : A Multiscale Powder Diffraction Investigation / M. Coduri, P. Masala, M. Allieta, I. Peral, M. Brunelli, C.A. Biffi, M. Scavini. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - 57:2(2018 Jan 15), pp. 879-891. [10.1021/acs.inorgchem.7b02896]

Phase Transformations in the CeO2-Sm2O3System : A Multiscale Powder Diffraction Investigation

Coduri, Mauro;Masala, Paolo;Allieta, Mattia;Scavini, Marco
2018-01-15

Abstract

The structure evolution in the CeO2-Sm2O3system is revisited by combining high resolution synchrotron powder diffraction with pair distribution function (PDF) to inquire about local, mesoscopic, and average structure. The CeO2fluorite structure undergoes two phase transformations by Sm doping, first to a cubic (C-type) and then to a monoclinic (B-type) phase. Whereas the C to B-phase separation occurs completely and on a long-range scale, no miscibility gap is detected between fluorite and C-type phases. The transformation rather occurs by growth of C-type nanodomains embedded in the fluorite matrix, without any long-range phase separation. A side effect of this mechanism is the ordering of the oxygen vacancies, which is detrimental for the application of doped ceria as an electrolyte in fuel cells. The results are discussed in the framework of other Y and Gd dopants, and the relationship between nanostructuring and the above equilibria is also investigated.
physical and theoretical chemistry; inorganic chemistry
Settore CHIM/02 - Chimica Fisica
Settore FIS/03 - Fisica della Materia
INORGANIC CHEMISTRY
Article (author)
File in questo prodotto:
File Dimensione Formato  
Final.pdf

accesso aperto

1.53 MB Adobe PDF Visualizza/Apri
acs.inorgchem.7b02896.pdf

non disponibili

5.49 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/554559
Citazioni
  • ???jsp.display-item.citation.pmc??? 3
  • Scopus 27
  • ???jsp.display-item.citation.isi??? 25
social impact