Epitaxial crystals of Bi2Pt2O7 pyrochlore through the transformation of δ -Bi2O3 fluorite
Bi Pt O pyrochlore is thought to be one of the most promising oxide catalysts for application in fuel cell technology. Unfortunately, direct film growth of Bi Pt O has not yet been achieved, owing to the difficulty of oxidizing platinum metal in the precursor material to Pt . In this work, in order to induce oxidation of the platinum, we annealed pulsed laser deposited films consisting of epitaxial δ-Bi O 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 Pt O . 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 O and Bi Pt O structures appears to facilitate the pyrochlore formation. These results provide the only route to date for the formation of epitaxial Bi Pt O . 2 2 7 2 2 7 2 3 2 2 7 2 3 2 2 7 2 2 7 4+
Gutiérrez-Llorente, Araceli; Joress, Howie; Woll, Arthur; Holtz, Megan E.; Ward, Matthew J.; Sullivan, Matthew C.; Muller, David A.; and Brock, Joel D., "Epitaxial crystals of Bi2Pt2O7 pyrochlore through the transformation of δ -Bi2O3 fluorite" (2015). Faculty Articles Indexed in Scopus. 998.