Dresden 2009 – wissenschaftliches Programm
O 19.6: Vortrag
Dienstag, 24. März 2009, 11:45–12:00, SCH A215
Electrocatalysis on Nanostructured Surfaces: Electrochemical Behviour of Ir(210) — •Khaled Soliman, Felice Simeone, Ludwig Kibler, and Timo Jacob — Institut für Elektrochemie, Universität Ulm, 89069 Ulm
Recently it was found that Ir(210) transforms to a nanostructured surface morphology with three-sided nanopyramids after oxygen adsorption and annealing in ultra high vacuum (UHV) . Motivated by this work we envisaged to prepare such nanofaceted surfaces outside a UHV system. We could show that faceted Ir(210) can indeed be prepared by inductive heating in presence of an inert atmosphere, which contains traces of oxygen . Such surfaces are of interest for electrocatalysis. In order to characterize Ir(210) cyclic voltammetry (CV) and STM measurements were carried out. In our CV-curves of faceted Ir(210) in sulfuric acid a characteristic needle-like peak appeared, which serves as indicator for the presence and quality of the nanofacets. The STM images showed a typical structure of faceted Ir(210) surface, which could be explained by theoretical calculations employing density functional theory and thermodynamic considerations . Finally, we performed first studies on the electrocatalytic behaviour of planar and nanofaceted Ir(210).
 I. Ermanoski, C. Kim, S. P. Kelty, T. E. Madey, Surf. Sci., 596, 89 (2005).  K. A. Soliman, F. C. Simeone and L. A. Kibler, Electrochem. Comm., 11, 31 (2008).  P. Kaghazchi, F. C. Simeone, K. A. Soliman, L. A. Kibler, T. Jacob, Faraday Discuss., 140, 69 (2008).