Epitaxial crystals of Bi{sub 2}Pt{sub 2}O{sub 7} pyrochlore through the transformation of δ–Bi{sub 2}O{sub 3} fluorite
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States)
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853 (United States)
- Department of Physics and Astronomy, Ithaca College, Ithaca, New York 14850 (United States)
Bi{sub 2}Pt{sub 2}O{sub 7} pyrochlore is thought to be one of the most promising oxide catalysts for application in fuel cell technology. Unfortunately, direct film growth of Bi{sub 2}Pt{sub 2}O{sub 7} has not yet been achieved, owing to the difficulty of oxidizing platinum metal in the precursor material to Pt{sup 4+}. In this work, in order to induce oxidation of the platinum, we annealed pulsed laser deposited films consisting of epitaxial δ–Bi{sub 2}O{sub 3} and co-deposited, comparatively disordered platinum. We present synchrotron x-ray diffraction results that show the nonuniform annealed films contain the first epitaxial crystals of Bi{sub 2}Pt{sub 2}O{sub 7}. We also visualized the pyrochlore structure by scanning transmission electron microscopy, and observed ordered cation vacancies in the epitaxial crystals formed in a bismuth-rich film but not in those formed in a platinum-rich film. The similarity between the δ–Bi{sub 2}O{sub 3} and Bi{sub 2}Pt{sub 2}O{sub 7} structures appears to facilitate the pyrochlore formation. These results provide the only route to date for the formation of epitaxial Bi{sub 2}Pt{sub 2}O{sub 7}.
- OSTI ID:
- 22415260
- Journal Information:
- APL materials, Vol. 3, Issue 3; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2166-532X
- Country of Publication:
- United States
- Language:
- English
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