Journal of Inorganic Materials ›› 2014, Vol. 29 ›› Issue (5): 539-544.DOI: 10.3724/SP.J.1077.2014.13410

• Research Paper • Previous Articles     Next Articles

Rietveld Structure Refinement and Raman Spectroscopy of Pyrochlore-type Oxygen-rich Ce2Zr2O8 Phase

XIE Hua1,2, WANG Lie-Lin1, LUO De-Li2   

  1. (1. Key Laboratory of Defensive Discipline on Nuclear Wastes and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010, China; 2. Key Laboratory of Surface physical and Chemistry, Mianyang 621907, China)
  • Received:2013-08-12 Revised:2013-10-25 Published:2014-05-20 Online:2014-04-24
  • About author:XIE Hua. E-mail: xiehua@swust.edu.cn
  • Supported by:

    National Natural Science Foundation of China (21101129); Program of Key Laboratory of Defensive Discipline on Nuclear Wastes and Environmental Safety (11zxnk08)

Abstract: Pyrochlore-type oxygen-rich Ce2Zr2O8 phase was prepared successfully by graphite reduction method. In order to compare the structure between Ce2Zr2O8 and Nd2Zr2O7, the pyrochlore Nd2Zr2O7 was selected as the substitute of CeZrO3.5+δ, the oxide precursor of Ce2Zr2O8. Experimental results show that excessive oxygen in the Ce2Zr2O8 structure mainly occupies the oxygen vacancies from the precursor structure. Oxygen ions diffusion in the precursor CeZrO3.5 structure does not destroy the ordering cation sublattice. Meanwhile, Zr-O ligands are transformed from octahedrons of co-top connection in the precursor to cubes of co-edge connection in the Ce2Zr2O8. The antiphase boundary density and Raman bands in comparison with?the precursor are improved significantly, suggesting the structure of Ce2Zr2O8 phase is in a metastable state. The characteristic structure facililates rapid adsorption or release of oxygen ions, providing structural feasibility for ideal candidate materials for automobile exhaust purification. However, the structure of Ce2Zr2O8 indicated that the radiation resistance and chemical stability may be downward when An2Zr2O7 pyrochlore under self irradiation condition transforms to the oxygen-rich phase An2Zr2O8.

Key words: Ce2Zr2O8, ordering cations, antiphase domain boundary, ligands

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