Accession Number:

ADA247108

Title:

Application of the A.C. Admittance Technique to Double Layer Studies on Polycrystalline Gold Electrodes

Descriptive Note:

Technical rept

Corporate Author:

CALIFORNIA UNIV DAVIS DEPT OF CHEMISTRY

Personal Author(s):

• Fawcett, W. R.
• Kovacova, Zuzana
• Motheo, Arthur J.
• Foss, Colby A., Jr

Report Date:

1992-02-24

Pagination or Media Count:

26.0

Abstract:

A detailed examination of the dependence of the a.c. admittance of a cell containing a polycrystalline gold electrode has been made in the double layer region as a function of d.c. potential, a.c. frequency and electrode history. It is shown that the interfacial impedance of a gold electrode with a carefully prepared surface can be treated under these circumstances as a constant phase element when it is in contact with an aqueous solution containing 0.05 M KClO4. Analysis of the frequency dependence of the cell impedance gives the surface inhomogeneity parameter n which tums out to be very close to unity. Although the electrode surface is only slightly inhomogeneous on a microscopic scale, a very large frequency dispersion of the impedance is observed experimentally. A method of estimating the true specific capacity of the electrode is presented, and conditions for carrying out the experiments in a reproducible manner discussed. double layer at goldsolution interface, a.c. admittance techniques, constant phase element model.

Descriptors:

• *ELECTRODES
• *ADMITTANCE
• FREQUENCY
• FUNCTIONS
• MODELS
• INTERFACES
• LAYERS
• PARAMETERS
• GOLD
• DISPERSIONS
• POLYCRYSTALLINE
• IMPEDANCE
• CONSTANTS
• CELLS
• REGIONS
• PHASE
• SURFACES
• SCALE

Subject Categories:

• Electrical and Electronic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE