ANION ABSORPTION ON THE (111) FACE OF SILVER

Differential capacity (admittance-impedance) measurements for a (111) face of silver in supra-pure solutions of NaF, Na2SO4 and NaCH3COO are analysed to obtain data on the specific adsorption of the above-mentioned anions. It is shown that the frequency dependence of the impedance of the electrochemical interface cannot be represented by an equivalent circuit consisting of the ohmic resistance (R(OMEGA)) and double-layer capacitance (C(dl)) connected in series in the presence of specific adsorption, The addition of a series combination of a resistance (R(ct)) and capacitance (C(ad)) in parallel with C(dl) gives a reasonable representation of the data. R(ct) permits the evaluation of some semi-quantitative information about the adsorption kinetics.