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

PDF Url : ADA191513

Report Date : 25 Feb 1988

Pagination or Media Count : 17

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 O=ads 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