On the Mechanism of the Reduction Process of the Hydrogen Ion at the Dropping Mercury Electrode. III. Experimental Part —The Half-wave Potential, Log-plot Analysis and the Reversibility of the Wave

The electrode reduction reaction of lead malate, involving deprotonated malate ion and a proton, between pK1 and pK2 values of the acid has been investigated. At pH < pK1 protonated ion participates and a proton is involved. The effect of ligand concentration on the half-wave potential of Pb2+ has been investigated and the stability constants of species so formed computed.

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Reduction of Cd(II) Ions in the Presence of Tetraethylammonium Cations. Adsorption Effect on the Electrode Process

Electrochem ◽

10.3390/electrochem2030027 ◽

2021 ◽

Vol 2 (3) ◽

pp. 415-426

Author(s):

Juan Torrent-Burgués

Keyword(s):

Mercury Electrode ◽

Reduction Process ◽

Inhibitory Effect ◽

Electrode Process ◽

Adsorption Effect ◽

A Value ◽

Half Wave ◽

Dropping Mercury Electrode ◽

Electrode Coverage ◽

Isotherm Equations

The effect of the adsorption of tetraethylammonium (TEA) cations, which present both ionic and organic characteristics, on the reduction of Cd(II) ions have been studied from dc and ac measurements at the dropping mercury electrode. The resistance to the charge transfer (Rct) and Warburg coefficient (σ) parameters have been determined through impedance measurements. Thus, the global velocity constant has been obtained. The reduction process of Cd(II) in perchloric media is reversible and is affected by the adsorption of TEA cations, especially at high TEA concentrations. Values of E1/2, half wave potential, and DO, diffusion coefficient, obtained from both dc and ac measurements agree. The velocity constants show a decrease as TEA concentration increases, with values ranging from 0.6 to 0.01 cm·s−1. The inhibitory effect of TEA adsorption on the electrode process and the relationship between electrode coverage, θ, and velocity constants, K, using several isotherm equations, have been discussed. The best fit was obtained with the equation K = 0K(1 − θ)a with an a value close to three, indicating a blocking effect and electrostatic repulsion due to TEA.

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On the Mechanism of the Reduction Process of the Hydrogen Ion at the Dropping Mercury Electrode. I. Theoretical Part

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.25.287 ◽

1952 ◽

Vol 25 (5) ◽

pp. 287-293 ◽

Cited By ~ 4

Author(s):

Reita Tamamushi

Keyword(s):

Mercury Electrode ◽

Reduction Process ◽

Hydrogen Ion ◽

Theoretical Part ◽

Dropping Mercury Electrode

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Direct current polarography of the ferrous-ferric oxolate system in the presence of alternating voltages

Australian Journal of Chemistry ◽

10.1071/ch9580009 ◽

1958 ◽

Vol 11 (1) ◽

pp. 9

Author(s):

P Beckmann ◽

GS Buchanan

Keyword(s):

Direct Current ◽

Active Substance ◽

Mercury Electrode ◽

Surface Active Substance ◽

Active Materials ◽

Wave Potential ◽

Half Wave ◽

Dropping Mercury Electrode ◽

Surface Active ◽

Alternating Voltage

The effect of the superposition of a small alternating voltage on the normal direct voltage applied to the dropping mercury electrode (D.M.E.) was investigated in the case of the ferrous-ferric oxalate system. The wave obtained was of the type found previously for ions which are reversibly reduced at the D.M.E. (e.g. Cd++ etc.). That is, the rectification of the A.C. produced a D.C. wave (the Z wave) which crossed the normal D.C. wave (the Y wave) at the half-wave potential (E�), When surface active materials were added (e.g. cyclohexanol) the reduction became " irreversible " and at certain concentrations of the surface active substance a maximum appeared on the Y wave of a somewhat unusual nature. The effect of a superposed alternating voltage was studied in these cases and it was found that the adsorption of the cyclohexanol was influenced by the presence of the alternating voltage.

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Half-wave potential-ph diagram for the parabenzoquinone system in n,n-dimethylformamide

Analytical Letters ◽

10.1080/00032716908051282 ◽

1969 ◽

Vol 2 (3) ◽

pp. 123-132 ◽

Cited By ~ 4

Author(s):

J. Badoz-lambling ◽

G. Demange-guerin

Keyword(s):

Wave Potential ◽

Half Wave Potential ◽

Half Wave

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Modified Carbon Nanotubes: Surface Properties and Activity in Oxygen Reduction Reaction

Catalysts ◽

10.3390/catal11111354 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1354

Author(s):

Vera Bogdanovskaya ◽

Inna Vernigor ◽

Marina Radina ◽

Vladimir Sobolev ◽

Vladimir Andreev ◽

...

Keyword(s):

Carbon Nanotubes ◽

Zeta Potential ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Surface Area ◽

Surface Properties ◽

Reduction Reaction ◽

Wave Potential ◽

Half Wave Potential ◽

Half Wave

In order to develop highly efficient and stable catalysts for oxygen reduction reaction (ORR) that do not contain precious metals, it is necessary to modify carbon nanotubes (CNT) and define the effect of the modification on their activity in the ORR. In this work, the modification of CNTs included functionalization by treatment in NaOH or HNO3 (soft and hard conditions, respectively) and subsequent doping with nitrogen (melamine was used as a precursor). The main parameters that determine the efficiency of modified CNT in ORR are composition and surface area (XPS, BET), hydrophilic–hydrophobic surface properties (method of standard contact porosimetry (MSP)) and zeta potential (dynamic light scattering method). The activity of CNT in ORR was assessed following half-wave potential, current density within kinetic potential range and the electrochemically active surface area (SEAS). The obtained results show that the modification of CNT with oxygen-containing groups leads to an increase in hydrophilicity and, consequently, SEAS, as well as the total (overall) current. Subsequent doping with nitrogen ensures further increase in SEAS, higher zeta potential and specific activity in ORR, reflected in the shift of the half-wave potential by 150 mV for CNTNaOH-N and 110 mV for CNTHNO3-N relative to CNTNaOH and CNTHNO3, respectively. Moreover, the introduction of N into the structure of CNTHNO3 increases their corrosion stability.

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Polarography of some coordination compounds of platinum. I. Hexammineplatinum (IV) and Tris(ethylenediamine)platinum(IV) ions

Australian Journal of Chemistry ◽

10.1071/ch9550158 ◽

1955 ◽

Vol 8 (2) ◽

pp. 158 ◽

Cited By ~ 7

Author(s):

JR Hall ◽

RA Plowman

Keyword(s):

Potassium Chloride ◽

Supporting Electrolyte ◽

Platinum Metal ◽

Potassium Nitrate ◽

Diffusion Current ◽

Polarographic Reduction ◽

Wave Potential ◽

Half Wave Potential ◽

Half Wave ◽

Continuous Discharge

The polarographic reduction of tris(ethylenediamine)platinum(IV) and the hexammineplatinum(IV) ions has been studied in potassium chloride, potassium nitrate, and potassium nitrate plus ammonia solutions. Both ions were reduced irreversibly producing similarly shaped waves, showing well-defined diffusion current regions corresponding to two-electron reductions of the complexes. A linear relationship existed between diffusion current and concentration within the range examined. In aqueous potassium chloride and potassium nitrate media, the waves contained slight inflexions at positions corresponding to one-electron additions. The phenomenon suggested the transient presence of platinum(III) ions, and indicated that the half-wave potential of the reduction of the complexes to the trivalent state was very close to the half-wave potential of the reduction from platinum(IV) to platinum(II). The values were so close together as to indicate the improbability of isolating the trivalent complexes. Gelatin enhanced the inflexion in the wave but shifted the wave in a more negative direction. An increased concentration of supporting electrolyte also shifted the wave to a more negative position. In all cases a continuous discharge began at about -1.3 V (v. S.C.E.). This discharge was so far removed from that of the potassium ions of the supporting electrolyte that it was attributed to the discharge of hydrogen. Since the initial reduction of the platinum complexes corresponded to a two-electron change, it can be represented by reduction to a tetrammine ion. It is postulated that at higher applied potentials (namely, -1.3 V v. S.C.E.) the reduction proceeded further, producing platinum metal. This platinum metal would be in an active state, insoluble in mercury, and being on the surface, would lower the overvoltage of hydrogen leading to its discharge at a more positive potential than on a pure mercury surface. This view was supported by the fact that gas bubbles were observed at the dropping electrode when a voltage greater than -1.3 V was applied to the electrode for some time. When ammonia was added to the supporting electrolyte, a wave, without an inflexion, and corresponding to an irreversible two-electron reduction, was obtained at more negative potentials. The bivalent tetrammineplatinum(II) and bis(ethylenediamine)platinum(II) ions also gave polarograms showing the continuous discharge of hydrogen.

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