Accession Number : AD0766821

Title :   Optical and Electrochemical Studies of Underpotential Deposition of Lead on Gold Evaporated and Single Crystal Electrodes.

Descriptive Note : Technical rept.,

Corporate Author : CASE WESTERN RESERVE UNIV CLEVELAND OHIO ELECTROCHEMISTRY RESEARCH LAB

Personal Author(s) : Adzic,Radoslav ; Yeager,Ernest ; Cahan,B. D.

Report Date : 15 JUL 1973

Pagination or Media Count : 50

Abstract : Linear sweep voltammetry and reflectance spectroscopy have been used to examine the under potential deposition of lead on gold in Pb(2+) containing HC104 solutions. The voltammetry curves and reflectance change data provide evidence that the lead is first deposited as ions although their effective ionic charge is probably reduced substantially from +2 through their strong interaction with the band structure of the gold substrate. At more cathodic potentials, still well below the reversible potential of bulk lead, a sharp transition is observed over a 5 to 10 mV range. This transition appears to involve a two dimensional phase transition leading to a metallic-like lead layer. Adsorption isotherms have been evaluated from the reflectance changes. A.c. electromodulation techniques and complex plane analysis have been used to examine the kinetics of the lead adsorption-desorption and to evaluate the apparent exchange current density for the process. (Modified author abstract)

Descriptors :   (*LEAD(METAL), *ELECTRODEPOSITION), REFLECTIVITY, OPTICAL PROPERTIES, GOLD, ELECTRODES, ADSORPTION, PHASE STUDIES, SURFACE PROPERTIES, IONS, POLAROGRAPHIC ANALYSIS

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE