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Láng GG, Horányi G. Comment on the paper “Kinetic calculations of Ni anodic dissolution from EIS” [J Solid State Electrochemistry (2005) 9:83]. J Solid State Electrochem 2006. [DOI: 10.1007/s10008-006-0146-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Horányi G, Láng GG. Double-layer phenomena in electrochemistry: Controversial views on some fundamental notions related to electrified interfaces. J Colloid Interface Sci 2006; 296:1-8. [PMID: 16480737 DOI: 10.1016/j.jcis.2006.01.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Revised: 01/10/2006] [Accepted: 01/10/2006] [Indexed: 11/28/2022]
Abstract
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. One of the most important aims of the present work was to demonstrate that independent of the thermodynamic considerations, the concept of electrosorption valency cannot be reconciled with elementary laws of electrochemistry. On the basis of analysis of real processes occurring in the interfacial layer of electrodes it was urged to avoid the treatment of some double-layer phenomena in terms of electrosorption valency in order to eliminate far-reaching misinterpretations leading to serious contradictions.
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Affiliation(s)
- G Horányi
- Research Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary.
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Láng GG, Rokob TA, Horányi G. 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. Ultramicroscopy 2005; 104:330-2. [PMID: 15899550 DOI: 10.1016/j.ultramic.2005.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 03/17/2005] [Indexed: 10/25/2022]
Abstract
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.
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Affiliation(s)
- G G Láng
- Department of Physical Chemistry, Eötvös Loránd University, Budapest 112, H-1518, Hungary.
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Láng G, Inzelt G, Vrabecz A, Horányi G. Electrochemical aspects of some specific features connected with the behavior of iron group metals in aqueous perchloric acid/perchlorate media. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2005.01.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Horányi G, Kálmán E. Anion specific adsorption on Fe2O3 and AlOOH nanoparticles in aqueous solutions: comparison with hematite and γ-Al2O3. J Colloid Interface Sci 2004; 269:315-9. [PMID: 14654390 DOI: 10.1016/s0021-9797(03)00750-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
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. It was found, however, that in contrast to the behavior of gamma-Al(2)O(3), nano-AlOOH dissolves at a significant rate at low pH values (pH<2). Thus the study of the pH dependence of the anion adsorption encounters difficulties at these pH values. Disregarding this fact, it can be concluded that no special effects can be observed in the anion adsorption onto the nano-oxides studied.
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Affiliation(s)
- G Horányi
- Research Laboratory of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, 1525, PO Box 17, Budapest, Hungary.
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Láng G, Vrabecz A, Horányi G. Radiotracer and analytical evidences proving the reduction of ClO4− ions at the cobalt/electrolyte solution interface. Electrochem commun 2003. [DOI: 10.1016/s1388-2481(03)00141-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Abstract
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. From the pH dependence it follows that the protonation of the surface should precede the specific anion adsorption. The results obtained are compared with those reported for TiO2 bulk electrodes.
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Affiliation(s)
- G Horányi
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, 1525 Budapest, Hungary.
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Abstract
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. In the case of benzoic acid the extent of adsorption with decreasing pH goes through a sharp maximum at a pH value not far from the pK (4.2) of the acid, while in the case of oxalic acid only a small decrease can be observed at very low pH values (pH<1). In indirect radiotracer studies using (35)S-labeled sulfate ions it was shown that the competitive adsorption of formic, malonic, maleic, and oxalic acids with sulfate ions depends on pH and the effect of the organic acid on the anion adsorption becomes pronounced at pH values about and above the pK of the acid. On the basis of these observations and considerations concerning the dissociation of the organic acids studied it is assumed that the specific adsorption of the anionic form of the acids takes place. It is, however, emphasized that the negative charge of the anions, consequently the electrostatic forces, do not play significant role in the adsorption.
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Affiliation(s)
- G Horányi
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, Budapest, 1525, Hungary.
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Horányi G, Joó P. Some Peculiarities in the Specific Adsorption of Phosphate Ions on Hematite and γ-Al2O3 as Reflected by Radiotracer Studies. J Colloid Interface Sci 2002; 247:12-7. [PMID: 16290435 DOI: 10.1006/jcis.2001.8103] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2001] [Accepted: 11/08/2001] [Indexed: 11/22/2022]
Abstract
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. On the other hand, it was found that the reversible adsorption of phosphate ions is accompanied by the formation of strongly chemisorbed species. Results obtained from a study of the competitive adsorption of sulfate and phosphate ions at various pH values are reported and interpreted. An attempt is made to correlate the experimental findings with the models for anion adsorption reported in the literature.
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Affiliation(s)
- G Horányi
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, Budapest, 1525, Hungary.
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Láng G, Aramata A, Horányi G. Some remarks on a method suggested for the distinction between SO42− and HSO42− ions adsorbed on an electrode. J Electroanal Chem (Lausanne) 2001. [DOI: 10.1016/s0022-0728(01)00410-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Horányi G, Joó P. Application of the Radiotracer Technique for the Study of the Specific Anion Adsorption on Al(2)O(3) in Acidic Medium. J Colloid Interface Sci 2000; 231:373-378. [PMID: 11049687 DOI: 10.1006/jcis.2000.7178] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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. A Langmuir-like adsorption isotherm describes the concentration dependence of the adsorption of sulfate species. It was found that the experimental results are very similar to those obtained in the case of hematite. Copyright 2000 Academic Press.
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Affiliation(s)
- G Horányi
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest, 1525, Hungary
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Horányi G, Joó P. In Situ Study of the Specific Adsorption of HSO(4)(-)/SO(4)(2-) Ions on Hematite by Radiotracer Technique. J Colloid Interface Sci 2000; 227:206-211. [PMID: 10860612 DOI: 10.1006/jcis.2000.6852] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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. A Langmuir-like adsorption isotherm describes the concentration dependence of the adsorption of sulfate species. It was found that the experimental results are in good agreement with the model suggested recently (Hug, S. J. J. Colloid Interface Sci. 188, 415 (1997)). Copyright 2000 Academic Press.
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Affiliation(s)
- G Horányi
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest, 1525, Hungary
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Láng G, Aramata A, Seo M, Horányi G. The link between the relative surface excesses determined by thermodynamic means and the surface excess concentration determined by the radiotracer method. J Electroanal Chem (Lausanne) 2000. [DOI: 10.1016/s0022-0728(00)00055-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Joó P, Horányi G. Radiotracer Study of the Specific Adsorption of Anions on Metal Oxides in Acid Media: An Experimental Approach. J Colloid Interface Sci 2000; 223:308-310. [PMID: 10700416 DOI: 10.1006/jcis.1999.6678] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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. Copyright 2000 Academic Press.
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Affiliation(s)
- P Joó
- Department of Colloid Chemistry, Kossuth Lajos University, Debrecen, H-4010, Hungary
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Inzelt G, Horányi G. Direct experimental evidence proving the formation of surface layers in the course of the reduction of Cr(VI) species at a gold electrode. J Electroanal Chem (Lausanne) 1999. [DOI: 10.1016/s0022-0728(99)00274-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Aramata A, Taguchi S, Fukuda T, Nakamura M, Horányi G. Underpotential deposition of zinc ions at single crystal electrodes and the effect of the adsorbed anions. Electrochim Acta 1998. [DOI: 10.1016/s0013-4686(98)00204-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Horányi G. Influence of the specific adsorption of anions on the "double layer region" of the cyclic voltammetric curves obtained with platinized platinum electrodes. J Solid State Electrochem 1998. [DOI: 10.1007/s100080050093] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Horányi G. Comment on the paper “A comparative voltammetric study of the Ir|H2SO4 and Ir|HClO4 aqueous interfaces” by Ines T.E. Fonseca, M. Irene Lopes, M. Teresa C. Portela [J. Electroanal. Chem. 415 (1996) 89]. J Electroanal Chem (Lausanne) 1997. [DOI: 10.1016/s0022-0728(97)00280-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Horányi G. A novel approach to platinized platinum electrodes: specific adsorption as a partition between the solution phase and the electrodeposited platinum black layer. J Electroanal Chem (Lausanne) 1996. [DOI: 10.1016/s0022-0728(96)04755-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wasberg M, Bácskai J, Inzelt G, Horányi G. The harmony of EQCM and radiotracer sorption results obtained in the course of voltammetric study of a rhodized electrode. J Electroanal Chem (Lausanne) 1996. [DOI: 10.1016/s0022-0728(96)04854-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Horányi G, Wasberg M. Study of the equilibrium underpotential deposition of copper and the accompanying anion adsorption on rhodized electrodes in the course of cyclic voltammetric measurements. J Electroanal Chem (Lausanne) 1996. [DOI: 10.1016/0022-0728(96)04621-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kolics A, Horányi G. Potentialities of a version of the radiotracer ‘foil’ (Joliot) method for sorption studies based on the measurements of X-radiation. Appl Radiat Isot 1996. [DOI: 10.1016/0969-8043(96)00009-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Martinusz K, Inzelt G, Horányi G. Comparative study of anion-involvement in redox transformations of poly(o-phenylene-diamine) (PPD) films by a coupled electrochemical and radiometric technique. J Electroanal Chem (Lausanne) 1996. [DOI: 10.1016/0022-0728(95)04331-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kolics A, Horányi G. Some considerations about the applicability of the in situ radiotracer “foil” method for the study of accumulation processes on compact stainless steel electrodes—II. Measurement of induced X-radiation. Electrochim Acta 1995. [DOI: 10.1016/0013-4686(95)00135-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Martinusz K, Inzelt G, Horányi G. Coupled electrochemical and radiometric study of anion migration in poly(o-phenylenediamine) films. J Electroanal Chem (Lausanne) 1995. [DOI: 10.1016/0022-0728(95)04095-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Wasberg M, Horányi G. Voltammetric and impinging jet study of the behaviour of rhodized electrodes in acidic perchlorate solutions. J Electroanal Chem (Lausanne) 1995. [DOI: 10.1016/0022-0728(94)03667-r] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Horányi G, Bakos I. Investigation of the electrodeposition and behaviour of Re layers by coupled radiochemical and electrochemical methods. J Electroanal Chem (Lausanne) 1994. [DOI: 10.1016/0022-0728(94)87066-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kolics A, Horányi G. The role of secondary effects in the radiochemical study of interfacial phenomena at metal electrodes. J Electroanal Chem (Lausanne) 1994. [DOI: 10.1016/0022-0728(94)03509-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kolics A, Horányi G. β-Backscattering: A radiochemical tool for the in-situ study of the electrochemical formation and dissolution of thin layers. J Electroanal Chem (Lausanne) 1994. [DOI: 10.1016/0022-0728(94)03353-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Horányi G, Bakos I. Coupled radiometric and electrochemical study of the reduction of TcO4− ions at a gold electrode in acidic medium (mechanistic aspects of Tc deposition). J Electroanal Chem (Lausanne) 1994. [DOI: 10.1016/0022-0728(93)03179-s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Bakos I, Horányi G. Study of the relationship between voltammetric behaviour and electrocatalytic activity in the reduction of ClO4− ions at platinized platinum electrodes. J Electroanal Chem (Lausanne) 1993. [DOI: 10.1016/0022-0728(93)80102-n] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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