title: Transmission electron microscopy studies of the nanoscale structure and chemistry of Pt50Ru50 electrocatalysts.
abstract: The structural and chemical heterogeneity of 2.5-nm Pt50Ru50 electrocatalysts was studied by transmission electron microscopy using selected area diffraction, lattice imaging, electron-energy loss spectroscopy, and energy-dispersive X-ray spectroscopy. The catalysts with the highest methanol oxidation activities exhibit oxidation-induced phase separation on the nanoscale to from Pt-rich metal embedded in Ru-rich hydrous and anhydrous oxide. Reduction of the oxide-on metal samples produces a true bimetallic face-centered cubic Pt50Ru50 alloy, with 275 times lower oxidation activity.
authors.affiliation: Surface Modification Branch, Naval Research Laboratory, Washington, DC 20375, USA.
authors.forename: Rhonda M
authors.initials: RM
authors.lastname: Stroud
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Long
authors.forename: Karen E
authors.initials: KE
authors.lastname: Swider-Lyons
authors.forename: Debra R
authors.initials: DR
authors.lastname: Rolison
mesh_terms: D000497:Alloys / Q000737:chemistry*; D002384:Catalysis; D004577:Electron Probe Microanalysis; D013058:Mass Spectrometry / Q000379:methods; D000432:Methanol / Q000378:metabolism; D008854:Microscopy, Electron / Q000295:instrumentation / Q000379:methods*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D010084:Oxidation-Reduction; D010984:Platinum / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D000497:Alloys; D010984:Platinum; D012428:Ruthenium; D000432:Methanol