Accession Number : ADA186578

Title :   Adsorption of Pyridine at the Au(100)-Solution Interface.

Descriptive Note : Technical rept. Jan-Jun 87,

Corporate Author : WATERLOO UNIV (ONTARIO) DEPT OF CHEMISTRY

Personal Author(s) : Stolberg, L ; Lipkowski, J ; Irish, D E

PDF Url : ADA186578

Report Date : 25 Sep 1987

Pagination or Media Count : 42

Abstract : Chronocoulometry has been used in order to quantitatively characterize the energetics of pyridine adsorption onto a gold(100) single crystal electrode surface. Over the potential region investigated (-0.8 to +0.6 V), three orientations of the pyridine molecules on the gold surface have been observed. The pyridine orientation is strongly influenced by the electrode potential. At a positively charged surface, the pyridine assumes a vertical orientation with the nitrogen atom facing the gold surface. A limiting surface concentration corresponding to 6x10 to the -10 mol/sq.cm was determined for the vertical orientation. Reorientation from the intermediate to the vertical orientation takes the form of a phase transition. The potential of the phase transition approximately coincides with the potential of zero charge. The free energies of adsorption, electrosorption valencies, potentials and charges of the maximum adsorption were determined for the flat and the vertical orientation of pyridine. Adsorption of pyridine on the Au(100) surface is compared with the adsorption at polycrystalline Au and mercury electrodes. Keywords: Chronocoulometry, Pyridine orientation, Coverage, Free energy, Adsorption, Au, Surface, Gold.

Descriptors :   *ADSORPTION, *COULOMETERS, *GOLD, *PYRIDINES, CHRONOMETERS, ELECTRODES, ENERGETIC PROPERTIES, ENERGY, FREE ENERGY, MERCURY, MOLECULES, ORIENTATION(DIRECTION), PHASE TRANSFORMATIONS, SURFACES, VERTICAL ORIENTATION, CRYSTAL LATTICES, CRYSTALLOGRAPHY, SURFACE CHEMISTRY, ELECTROLYTES, FREE ENERGY, ION EXCHANGE

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE