Accession Number:

ADA191513

Title:

The Formation of Adsorbed O(2-) and OH(-) on a Ag Electrode in Dilute CrO4(-2) Electrolytes.

Descriptive Note:

Technical rept.,

Corporate Author:

AMHERST COLL MA DEPT OF CHEMISTRY

Personal Author(s):

• Dorain, Paul B.
• Bates, Jennifer L.

Report Date:

1988-02-25

Pagination or Media Count:

17.0

Abstract:

Surface enhanced Raman scattering has been used to detect in situ the formation of O and OH- adsorbed on a Ag electrode in an aqueous solution of 25 micromolar Na2Cr2O7 and .01 to .001 M KC1. Both oxide and hydroxide adsorbates are observed after completion of an oxidation-reduction cycle in a standard voltammetry experiment. As the Ag electrode voltage is swept cathodically, the Oads is protonated to form more OH-ads but, unlike in MnO4- solutions, no further protonation to form H20 occurs at any cell voltage. The addition of O2 gas to the electrolyte deprotonates the adsorbed OH- to form an oxide covered surface. These results for CrO4 solutions are contrasted with previous results for MnO4 electrolytes to obtain information about the nature of the metal-solution interface in chromate passivated metal surfaces. Keywords Catalysis, Passivation, Metal surfaces, Protonation, Metal oxide absorbates, Silver, Electrodes, Hydroxides.

Descriptors:

• *CHROMATES
• *ELECTROLYTIC CELLS
• *HYDROXIDES
• *SILVER
• ABSORBERS(MATERIALS)
• CATALYSIS
• CYCLES
• ELECTRODES
• LIGHT SCATTERING
• METALS
• OXIDATION REDUCTION REACTIONS
• OXIDES
• PASSIVITY
• RAMAN SPECTRA
• SOLUTIONS(MIXTURES)
• SURFACES
• VOLTAGE
• VOLTAMMETRY
• WATER

Subject Categories:

• Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE