Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 20: Solid / liquid interfaces II

O 20.7: Vortrag

Montag, 14. März 2011, 18:45–19:00, WIL B321

Dealloying studies of Cu3Pd single crystal surfaces — •Shilan Meimandi and Frank Uwe Renner — Max Planck Institute for Iron Research, Max Planck Strasse 1, 40237 Düsseldorf

Binary noble metal alloys serve as model cases for dealloying in the context of corrosion studies [1]. Dealloying is a common corrosion process during which the more active element of an alloy is selectively dissolved into the electrolyte. Several aspects of formation of porous surface during dealloying has not completely been understood. The nano-porous metals formed by dealloying methods have application potential in a variety of fields such as catalysts, actuators, and biomedical sensors. The Cu-Pd system is interesting as a model system for corrosion as well as a potential catalyst material. The initial dealloying and selective dissolution of single-crystals Cu3Pd (111) and Cu3Pd (100) in 0.1 M H2SO4 have been studied. With in-situ X-ray diffraction, we observed the epitaxial Pd layer peak by increasing the potential close to the critical potential. Also with Ex-Situ atomic force microscopy (AFM), the formation of nanoscale islands of Pd (5-25 nm) as nobler metal have been revealed. Our aim is to study the initial steps of dealloying of well-defined Cu-Pd surfaces on the atomic scale and to compare the results to the Cu-Au system [2]. [1] R.Newman, K.Sieradzki, Science 263 (1994), 1708. [2] Renner et al., Physical Review B 77 (2008), 235433