Double-layer phenomena in electrochemistry: controversial views on some fundamental notions related to electrified interfaces.

The problem of the distinction between the so-called free charge and the thermodynamic (total) charge of electrodes was discussed in the light of the relevant IUPAC definitions calling attention to the strict relationships existing between charge and mass balances during the formation of a double layer at electrodes or/and particles. It is demonstrated that the origins of controversial views concerning partial charge transfer and electrosorption valency, notions widely used nowadays in the electrochemical literature, could be ascribed to confusion of the free and thermodynamic charges. Although there are, even if sporadic, evidences and theoretical considerations in the literature proving that electrosorption valency as usually defined is an extrathermodynamic and self-contradictory concept, it is widely used by many authors for the interpretation of electrosorption phenomena.

Some peculiarities in the specific adsorption of phosphate ions on hematite and gamma-Al2O3 as reflected by radiotracer studies.

The specific adsorption of radiolabeled phosphate ions from perchlorate supporting electrolyte onto gamma-Al2O3 and hematite powder has been investigated. The pH dependence of the adsorption of phosphate species was compared with that of sulfate ions. It was demonstrated that in contrast to the behavior of sulfate ions the pH dependence of phosphate ions goes through a maximum.

Investigation of the specific adsorption of sulfate ions on powdered TiO2.

The specific adsorption of radiolabeled sulfate ions from perchlorate supporting electrolyte onto TiO2 powder (anatase) has been investigated. The pH and concentration dependence of the adsorption was determined. Langmuir-like adsorption behavior similar to that on other oxides was found.

Comments on "Observation of the surface stress induced in microcantilevers by electrochemical redox processes" by F. Tian, J.H. Pei, D.L. Hedden, G.M. Brown, T. Thundat.

Critical remarks have been formulated in connection with the surface stress measurements reported by Tian et al. It has been shown that due to the shortcomings of the experimental procedure some conclusions of the authors are hardly acceptable.

Anion specific adsorption on Fe2O3 and AlOOH nanoparticles in aqueous solutions: comparison with hematite and gamma-Al2O3.

The specific adsorption of radiolabeled sulfate and phosphate ions from perchlorate supporting electrolyte onto nano-AlOOH and nano-Fe(2)O(3) powder has been investigated. The pH dependence of the adsorption of anions onto nanopowders was compared with that of the same ions onto gamma-Al(2)O(3) and hematite. It was demonstrated that the character of the pH dependence of the adsorption is very similar in the comparable cases.

Specific adsorption of simple organic acids on metal(hydr)oxides: a radiotracer approach.

The pH dependence of adsorption of (14)C-labeled benzoic and oxalic acids on gamma-Al(2)O(3) and hematite was studied in acid medium in the presence of 0.5 mol dm(-3) NaClO(4) supporting electrolyte. It was found that the adsorption of the organic species starts at pH values where the protonation of the oxide surface takes place.

Application of the Radiotracer Technique for the Study of the Specific Anion Adsorption on Al(2)O(3) in Acidic Medium.

The specific adsorption of radiolabeled anions (sulfate, chloride) from perchlorate supporting electrolyte on gamma-Al(2)O(3) powder has been investigated. It was demonstrated that a measurable adsorption occurs only at pH values under pH 6. The adsorption capacity of a given amount of gamma-Al(2)O(3) powder tends to a limiting value with decreasing pH.

In Situ Study of the Specific Adsorption of HSO(4)(-)/SO(4)(2-) Ions on Hematite by Radiotracer Technique.

The specific adsorption of radiolabeled sulfate ions from perchlorate supporting electrolyte on hematite powder has been investigated. It was demonstrated that a measurable adsorption occurs only at pH values under 5. The adsorption capacity of a given amount of hematite powder tends to a limiting value with decreasing pH.

Radiotracer Study of the Specific Adsorption of Anions on Metal Oxides in Acid Media: An Experimental Approach.

The specific adsorption of anions (HSO(4)(-), H(2)PO(4)(-), and Cl(-)) was studied at Fe(2)O(3), ZnO, and CuO surfaces by the radiotracer technique in strongly acidic medium (1 M HClO(4)). A significant specific adsorption of HSO(4)(-) and H(2)PO(4)(-) ions was found in all cases studied while no measurable adsorption of Cl(-) ions was observed. In the cases of ZnO and CuO, the specific adsorption takes place over the course of continuous dissolution of the oxide.