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Title: Adsorption of acetic acid at platinum and gold electrodes: a combined infrared spectroscopic and radiotracer study

Journal Article · · J. Phys. Chem.; (United States)
DOI:https://doi.org/10.1021/j100317a044· OSTI ID:5217995

The potential-dependent specific adsorption of acetic acid and acetate at polycrystalline platinum- and gold-aqueous interfaces has been examined by potential-difference infrared spectroscopy (PDIRS) in conjunction with quantitative surface concentration measurements using the radiotracer technique. Both the infrared and radiotracer measurements utilize a similar thin-layer solution arrangement. Extensive adsorption of acetic acid occurs at both platinum and gold, which increases at more positive potentials and reaches a maximum at the onset of anodic oxide formation. The PDIR spectra contain several features identified with solution acetic acid in the 1200-1800-cm/sup -1/ region, including v/sub C==O/ and v/sub C-O/ bands at 1710 and 1280 cm/sup -1/, respectively, arising from adsorption-induced changes in the thin-layer solution composition as well as a single band, at 1415 and 1400 cm/sup -1/ on platinum and gold, restively, due to adsorbed acetic acid. The intensity of the former bands can by employed to evaluate the extent of adsorption as a function of potential; the results are in semiquantitative agreement with the surface concentration-potential data from radiotracer measurements. In view of the infrared spectra together with the observed absence of acetate adsorption, the most likely modes of acetic acid adsorption involve hydrogen bonding between the carbonyl oxygen and inner-layer water molecules, of by self-association to form dimers or chain structures

Research Organization:
Purdue Univ., West Lafayette, IN (USA)
OSTI ID:
5217995
Journal Information:
J. Phys. Chem.; (United States), Vol. 92:6
Country of Publication:
United States
Language:
English