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O: Fachverband Oberflächenphysik

O 10: Metal/Water Interfaces: Structure and Reactivity

O 10.1: Vortrag

Montag, 16. März 2015, 15:00–15:15, HE 101

Adsorption of water and anions on noble metal electrodes: a surface vibrational spectroscopy study — •Yujin Tong, Martin Wolf, and R. Kramer Campen — Fritz-Haber-Institut, Abt. Physikalische Chemie, 14195 Berlin, Germany

Reactions at noble metal electrode / electrolyte solution interfaces play a key role in electrochemistry. Despite their importance, our understanding of the mechanisms underlying this chemistry is still surprisingly limited. For example, the interpretation of the features of cyclic voltamograms for platinum single crystals in contact with various electrolyte solutions is still essentially speculative (e.g. see Catalysis Today, 202 (2013) 105). In these and similar systems the principle obstacle towards insight is a lack of an in-situ experimental probe of the population and structure of adsorbed hydrogen, hydroxyl groups, water and anions. Here we overcome this challenge by employing surface specific vibrational spectroscopy, Sum Frequency Generation (SFG), within a flow thin layer electrochemical cell, to concurrently characterize the potential dependent population and structure of surface hydroxyl, water, anions and reactive intermediates at Au and Pt surfaces during the electrochemical oxidation of formic acid. This approach allows the clear identification of bridge-bonded formate, interfacial hydroxyl and water and the evolution of each of these species as a function of potential.