Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)
O 42.72: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
(111)-Textured Platinum Thin-Layer Electrodes on α-Al2O3(0001) for Spectro-Electrochemistry — •Björn Braunschweig, Alexej Mitin, and Winfried Daum — Institut für Physik und Physikalische Technologien, TU Clausthal, Leibnizstrasse 4, D-38678 Clausthal-Zellerfeld
The use of infrared vibrational spectroscopy to study electrochemical reactions on surfaces of bulk metal electrodes in aqueous electrolytes is often impaired by diffusion limitations as thin-layer electrolytes are required to minimize IR absorption in the liquid. Alternatively, thin-layer electrodes on IR-transparent substrates may be used to access the metal-electrolyte interface by IR transmission through the solids. While the latter strategy does not suffer from diffusion limitations of the electrolyte, it usually lacks the advantages of well-defined, single-crystalline electrode surfaces desired for model studies. We report the preparation of well-characterized Pt thin-film electrodes suitable for spectro-electrochemistry. Thin Pt layers with a thickness of 3 to 15 nm were grown by vapor deposition on atomically smooth α-Al2O3(0001) single crystal surfaces and characterized by AES, cyclic voltammetry, AFM and STM. We used iodine adsorption to characterize the crystallographic surface orientation of our Pt films. Atomically resolved STM images of the iodine adlayer on the thin films reveal the same superstructures as found on Pt(111) bulk single crystals and demonstrate high structural order and (111) texture of our films. The effects of growth temperature and film thickness on the surface morphology of the thin-film electrodes are discussed.