Structure of Nano‐sized CeO2 Materials: Combined Scattering and Spectroscopic Investigations |
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| Authors: | Huw R Marchbank Adam H Clark Dr Timothy I Hyde Dr Helen Y Playford Dr Matthew G Tucker Dr David Thompsett Dr Janet M Fisher Dr Karena W Chapman Kevin A Beyer Dr Manuel Monte Dr Alessandro Longo Prof Gopinathan Sankar |
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| Affiliation: | 1. Department of Chemistry, University College London, London, UK;2. Johnson Matthey Technology Centre, Reading, UK;3. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, UK;4. Diamond Light Source, Didcot, Oxon, UK;5. Spallation Neutron Source, Oak Ridge, TN, USA;6. X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, USA;7. ESRF-The European Synchrotron, CS40220, Grenoble, Cedex 9, France;8. Netherlands Organization for Scientific Research (NWO), ESRF-The European Synchrotron, CS40220, Grenoble, Cedex 9, France;9. CNR-ISMN, Consiglio Nazionale delle Ricerche, Istituto per lo Studio dei Materiali Nanostrutturati, Via, Palermo, Italy |
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| Abstract: | The structure of several nano‐sized ceria, CeO2, systems was investigated using neutron and X‐ray diffraction and X‐ray absorption spectroscopy. Whilst both diffraction and total pair distribution functions (PDFs) revealed that in all of the samples the occupancy of both Ce4+ and O2? are very close to the ideal stoichiometry, the analysis using Reverse Monte Carlo technique revealed significant disorder around oxygen atoms in the nano‐sized ceria samples in comparison to the highly crystalline NIST standard. In addition, the analysis revealed that the main differences observed in the pair correlations from various X‐ray and neutron diffraction techniques were attributable to the particle size of the CeO2 prepared by the reported three methods. Furthermore, detailed analysis of the Ce L3‐ and K‐edge EXAFS data support this finding; in particular the decrease in higher shell coordination numbers with respect to the NIST standard, is attributed to differences in particle size. |
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| Keywords: | ceria EXAFS pair distribution functions Reverse Monte Carlo Rietveld analysis |
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