Epitaxial crystals of Bi₂Pt₂O₇ pyrochlore through the transformation of δ–Bi₂O₃ fluorite
Bi₂Pt₂O₇ pyrochlore is thought to be one of the most promising oxide catalysts for application in fuel cell technology. Unfortunately, direct film growth of Bi₂Pt₂O₇ has not yet been achieved, owing to the difficulty of oxidizing platinum metal in the precursor material to Pt⁴⁺. In this work, in order to induce oxidation of the platinum, we annealed pulsed laser deposited films consisting of epitaxial δ–Bi₂O₃ 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 Bi₂Pt₂O₇. 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–Bi₂O₃ and Bi₂Pt₂O₇ structures appears to facilitate the pyrochlore formation. These results provide the only route to date for the formation of epitaxial Bi₂Pt₂O₇.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Energy Materials Center at Cornell (EMC2); Cornell Univ., Ithaca, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0001086
- OSTI ID:
- 1203554
- Journal Information:
- APL Materials, Vol. 3, Issue 3; ISSN 2166-532X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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