Calculated free energies of absorption of halide and hydroxide ions by mercury, silver, and gold electrodes

Abstract

The free energies of specific adsorption (AG°) for Br-, Cl-, F-, and OHin aqueous solution on Hg, Ag, and Au electrodes are calculated. The model includes metal-ion interactions, ion-water interactions, watermetal interactions, and Born energy contributions. For the halide ions, the calculated AG°a gree with previously reported experimental trends in adsorption although the magnitudes of AG°are too great. For QHadsorption, the calculated AG°do not agree with experimental data; reasons for the discrepancy are discussed. Adsorption for Brand Clis accompanied by loss of primary waters of hydration and the ions situate in the inner Helmholtz plane. The Fand OHions are negligibly dehydrated and adsorb in the outer Helmholtz plane.(1) This work was performed under the auspices of the U. 8. Atomic Energy Commission.

Bromide adsorption on silver in alkaline solution: A surface analytical study

“…29,421. Obviously, the Gibbs energy of adsorption for Br-on Ag (AGAfl,=-72.3kJ/mol [43]) is larger compared to OH-(AGAg/oH-=-14.2kJ/mol) or C1-on silver (AG~,,-=-62.8 kl/mol) [43]. In addition, the anodic oxide layers formed for potentials positive to ca.…”

Halide-Gated Molecular Release from Nanoporous Gold Thin Films

“…Release profile of fluorescein into 0.1 mM elution media of NaF, NaCl, NaBr, and NaI. Inset: Corresponding half-lives of the release versus free energy of adsorption of halides onto gold (theoretical calculation values from Bodé et al).…”

“…The similarity between the release rates for Cl – , Br – , and I – is likely due to the ionic strength of 0.1 mM still being high enough that Mechanism 1 contribution is not negligible. For providing further insight into the relationship between the spontaneity of halide adsorption onto gold surface and the resultant release rate, we used free energy (Δ G ) of adsorption of halides onto gold electrode obtained by theoretical calculations by Bodé et al (Figure inset). The monotonic trend shows that halide adsorption becomes more favorable in the order of F – < Cl – < Br – , with a corresponding decrease in the half-life of the release.…”

“…For providing further insight into the relationship between the spontaneity of halide adsorption onto gold surface and the resultant release rate, we used free energy (Δ G ) of adsorption of halides onto gold electrode obtained by theoretical calculations by Bodé et al (Figure inset). The monotonic trend shows that halide adsorption becomes more favorable in the order of F – < Cl – < Br – , with a corresponding decrease in the half-life of the release. It is worth mentioning that iodine is an established gold etchant and halide additives can modify np-Au morphology during dealloying. , This highlights that the iodine–gold affinity is so high that it exhibits a chemical interaction and also suggests the possibility that halide-gated release may be influenced by halide-mediated restructuring (via enhanced gold surface diffusion) of the gold surface .…”

Electrocatalytic conversion of carbon dioxide to fuels: a review on the interaction between CO2 and the liquid electrolyte

“…Different anions exhibit different tendency for adsorption on an electrode surface. For example, the Gibb's free energy for adsorption of Cl − (−15 kcal/mol) is more favorable than OH − (−3.4 kcal/mol) on Ag electrode, as illustrated in Figure . The adsorbed anions on the electrode surface can possibly interact with intermediates during CO 2 reduction.…”