%0 Journal Article
%A Wandlowski, T.
%A Ataka, K.
%A Pronkin, S.
%A Diesing, D.
%T Surface Enhanced Infrared Spectroscopy - Au(111-20nm)/Sulphuric Acid - New Aspects and Challanges
%J Electrochimica acta
%V 49
%@ 0013-4686
%C New York, NY [u.a.]
%I Elsevier
%M PreJuSER-30246
%P 1233 - 1247
%D 2004
%Z Record converted from VDB: 12.11.2012
%X The structure and orientation of water molecules on Au(1 1 1-20nm) film electrodes in contact with aqueous sulphuric acid solution was studied by surface enhanced infrared reflection-absorption spectroscopy (SEIRAS) employing an attenuated total reflection (ATR) configuration (ATR-SEIRAS) with a vertical spectroelectrochemical cell. The spectrum of interfacial water is strongly dependent on electrode potential, ionic strength and pH. Coadsorption of hydronium ions with weakly hydrogen-bonded water molecules was found at E < E-pzc. At E > E-pzc strong hydrogen-bonding among water molecules and to coadsorbed sulphate species exists. Based on pH-dependent electrochemical, spectroscopic and in situ STM investigations, a new model is suggested to represent the ordered (root3 x root7) adlayer at maximum sulphate coverage theta = 0.2: a Zundel or hydrated hydronium ion H5O2+, in which one proton is shared between two water molecules, bridges adjacent sulphate species via hydrogen-bonds along the main diagonal of the (root3 x root7) unit cell. This alternating arrangement gives rise to a long-range ordered, 2D network of sulphate and water species interconnected by hydrogen-bonds, and capable to form hydrogen-bonds with second-layer water species. The suggested model is consistent with all experimental observations as well as predictions from quantum-chemical and molecular dynamic simulations. (C) 2003 Elsevier Ltd. All rights reserved.
%K J (WoSType)
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000189226200006
%R 10.1016/j.electacta.2003.06.002
%U https://juser.fz-juelich.de/record/30246