IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electrochemistry and Fluid-Solid Interfaces Monday Sessions
       Session EC-MoM

Paper EC-MoM5
Ruthenium, Osmium, and Palladium Modified Platinum Elecrodes: Surface Structure and Reactivity

Monday, October 29, 2001, 11:00 am, Room 111

Session: Surface Processes in Electrocatalysis
Presenter: A. Crown, University of Illinois at Urbana-Champaign
Authors: A. Crown, University of Illinois at Urbana-Champaign
A. Wieckowski, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
We have used Scanning Tunneling Microscopy (STM) to examine spontaneously deposited ruthenium and osmium adlayers on the well-defined Pt(111), Pt(100), and Pt(110) electrodes.@footnote 1,2@ Clearly, ruthenium and osmium are deposited as arrays of surface islands, as in the case of ruthenium deposits obtained by electrolysis.@footnote 3@ Using STM, we have calculated ruthenium and osmium coverage values obtained by spontaneous deposition for various deposition times. The islands formed are mainly monoatomic--only a small fraction of the islands, depending on the Pt face, display a second monolayer deposit. Using in-situ STM, two-dimensional motions (or surface rearrangements) of highly structured islands of electrodeposited ruthenium, osmium, and palladium will be studied. The surface motions of platinum surface atoms, those of adsorbed carbon monoxide generated from methanol, and oxygen-containing species will also be investigated. We will attempt to address the surface mobility of the islands at various admetal coverage values. Examination, in situ, of the growth process will further elucidate the formation process, e.g., whether the islands tend to merge when the surface is exposed to a supporting electrolyte. Electrode potential will also be adjusted to examine the surface structure changes. The reactivity of these surfaces with respect to small organic compounds will also be examined. These experiments will lead us to the development of specific surface dynamics-reactivity relationships for the field of electrochemical surface science, with regards to surface poisoning phenomena and, in general, to electrocatalysis, including fuel cell catalysis. @FootnoteText@ @footnote 1@ Crown, A., Moraes, I.R.; Wieckowski, A.; J. Electroanal. Chem., 2001, 500, 333. @footnote 2@ Crown, A.; Wieckowski, A.; PCCP, in press. @footnote 3@ S. Cramm, K. A. Friedrich, K.-P. Geyzers, U. Stimming and R. Vogel, Fresenius J. Electroanal. Chem. 1997, 358, 189-192. .