Specific adsorption of halide and pseudohalide ions at electrochemically roughened versus smooth silver-aqueous interfaces

Joseph T Hupp, D. Larkin, Michael J. Weaver

Research output: Contribution to journalArticle

113 Citations (Scopus)

Abstract

The differential capacitance of electrochemically roughened silver surfaces in mixed perchlorate electrolytes containing chloride, bromide, iodide, thiocyanate, or azide anions has been measured as a function of electrode potential and anion concentration. These results are compared with corresponding data for electropolished silver in order to ascertain the influence of surface roughening on the double-layer structure and composition of polycrystalline silver-aqueous interfaces. The surface concentrations of specifically adsorbed anions were obtained from these capacitance-potential data using a "Hurwitz-Parsons" type of analysis. Although electrochemical roughening by means of a conventional oxidation-reduction cycle in chloride media is a prerequisite to the appearance of Surface-Enhanced Raman Scattering (SERS) for these adsorbates, it yields only moderate (ca. 1.5- to 2-fold) increases in the actual surface area and has a relatively minor effect on their average surface concentration. However, roughening does induce noticeable changes in the morphology of the capacitance-potential curves which are traced to alterations in the surface-crystallite structure. Comparisons between the potential dependence of SERS with corresponding capacitance-potential data indicate that anion coverages close to a monolayer are necessary for stable SERS. This is attributed to the stabilization of Raman-active silver clusters by surrounding adsorbed anions.

Original languageEnglish
Pages (from-to)429-451
Number of pages23
JournalSurface Science
Volume125
Issue number2
DOIs
Publication statusPublished - Feb 2 1983

Fingerprint

Silver
halides
silver
Ions
Adsorption
adsorption
Anions
Negative ions
ions
anions
Capacitance
capacitance
Raman scattering
Raman spectra
Chlorides
chlorides
Azides
Iodides
Adsorbates
perchlorates

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces

Cite this

Specific adsorption of halide and pseudohalide ions at electrochemically roughened versus smooth silver-aqueous interfaces. / Hupp, Joseph T; Larkin, D.; Weaver, Michael J.

In: Surface Science, Vol. 125, No. 2, 02.02.1983, p. 429-451.

Research output: Contribution to journalArticle

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