Accession Number : ADA266786


Title :   Structural and Dynamical Aspects of Electrodeposition


Descriptive Note : Final rept. 26 Feb 90-15 Feb 93,


Corporate Author : CORNELL UNIV ITHACA NY DEPT OF CHEMISTRY


Personal Author(s) : Abruna, Hector D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a266786.pdf


Report Date : May 1993


Pagination or Media Count : 6


Abstract : The basic aim of this contract was to investigate structural and dynamical aspects of electrochemical phase formation. In these investigations we have emphasized the underpotential deposition of metal mono and multilayers employing electrochemical, x-ray based and ultra high vacuum surface spectroscopic techniques. We have been able to study: (1) The underpotential deposition of silver on a Pt(111) electrode as function of (a) concentration (b) potential sweep rate (c) the presence of co-adsorbates From these studies we have been able to determine that two monolayers of silver are deposited at underpotentials and that the stability of the second layer is a strong function of the concentration of silver in solution and the potential sweep rate. The presence of co-adsorbates can have a profound influence in the deposition and the magnitude of this effect(s) is strongly dependent on the type of adsorbate employed. (2) The underpotential deposition of copper on an iodine covered platinum surface by x-ray based techniques with emphasis on: (a) isotherms derived from electrochemical and x-ray based measurements (b) mode of deposition (c) structure of the copper layer We have found that isotherms derived from x- ray based measurements consistently yield a significantly higher coverage (relative to electrochemically derived isothems) that we ascribe to copper species weakly associated with the interface. We have also found that the deposition appears to obey a mechanism where sites deeper in the platinum surface are occupied first and that sites further up are the progressively occupied. The structure of the copper appears to be strongly influenced by the chemisorbed iodine. The copper atoms appear to occupy bridge sites on the surface.


Descriptors :   *ELECTRODEPOSITION , METALS , STABILITY , INTERFACES , STRUCTURES , VACUUM , ELECTROCHEMISTRY , X RAYS , PHASE , DEPOSITION , HIGH VACUUM , COPPER , ELECTRODES , IODINE , PLATINUM , SILVER , ISOTHERMS , ADSORBATES


Subject Categories : Fabrication Metallurgy


Distribution Statement : APPROVED FOR PUBLIC RELEASE