Mechanosynthesis and structural characterization of nanocrystalline Ce_1-xY_xO_2-δ (x=0.1-0.35) solid solutions

Abstract A series of nanostructured fluorite-type Ce_1-xY_xO_2-δ (0≤x≤0.35) solid solutions, prepared via high-energy milling of the CeO₂/Y₂O₃ mixtures, are investigated by XRD, HR-TEM, EDS and Raman spectroscopy. For the first time, complementary information on both the long-range and short-range structural features of mechanosynthesized Ce_1-xY_xO_2-δ, obtained by Rietveld analysis of XRD data and Raman spectroscopy, is provided. The lattice parameters of the as-prepared solid solutions decrease with increasing yttrium content. Rietveld refinements of the XRD data reveal increase in microstrains in the host ceria lattice as a consequence of yttrium incorporation. Raman spectra are directly affected by the presence of oxygen vacancies; their existence is evidenced by the presence of vibration modes at ~560 and ~600 cm^-1. The detailed spectroscopic investigations enable us to separate extrinsic and intrinsic origin of oxygen vacancies. It is demonstrated that mechanosynthesis can be successfully employed in the one-step preparation of nanocrystalline Ce_1-xY_xO_2-δ solid solutions.