Specific adsorption of Cl–, Br–, and I– ions on liquid In–Ga electrode from dimethyl formamide solutions with a constant ionic strength

Autor: B. B. Damaskin, V. V. Emets
Rok vydání: 2015
Předmět:
Zdroj: Russian Journal of Electrochemistry. 51:1149-1156
ISSN: 1608-3342
1023-1935
DOI: 10.1134/s1023193515120046
Popis: The differential capacitance curves were measured with an ac bridge in the (In–Ga)/[DMF + 0.1m M LiCl + 0.1(1–m) M LiClO4], (In–Ga)/[DMF + 0.1m M LiBr + 0.1(1–m) M LiClO4], and (In–Ga)/[DMF + 0.1m M LiI + 0.1(1–m) M LiClO4] (DMF is dimethyl formamide) systems at the following fractions m of surface-active anion: 0, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, and 1. The data on the specific adsorption of Cl–, Br–, and I– anions in these systems can be quantitatively described by the Frumkin’s isotherm. The free energy of Cl–, Br–, and I– adsorption (ΔG ads) is a quadratic function of electrode charge. It is found that, at the (In–Ga)/DMF interface, as well as at the Ga/DMF interface, ΔG ads varies in the series I– < Br– < Cl–. An analysis indicates conclusively that the series of surface activity of halide ions is reversed when we pass from the Hg/DMF and Bi/DMF interfaces to the Ga/DMF and (In–Ga)/DMF interfaces. A change of the solvent in the transition from (In–Ga)/N-methyl formamide interface to the (In–Ga)/dimethyl formamide interface is also accompanied by the transition from the common to the reversed series of surface activity of halide ions.
Databáze: OpenAIRE
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