Quantitative Voltammetry in Weakly Supported Media. Two Electron Transfer, Chronoamperometry of Electrodeposition and Stripping for Cadmium at Microhemispherical Mercury Electrodes

2009 ◽  
Vol 113 (34) ◽  
pp. 15320-15325 ◽  
Author(s):  
Juan G. Limon-Petersen ◽  
Edmund J. F. Dickinson ◽  
Neil V. Rees ◽  
Richard G. Compton
Keyword(s):  
Electron Transfer ◽  
Mercury Electrodes

Some Aspects of the Electroreduction of Niazid to Nicotinamide on Mercury Electrodes in Acidic Media

1992 ◽  
Vol 57 (9) ◽  
pp. 1836-1842 ◽  
Author(s):  
Rafael Marín Galvín ◽  
José Miguel Rodríguez Mellado
Keyword(s):  
Electron Transfer ◽  
Essential Role ◽  
Uv Spectroscopy ◽  
Acidic Media ◽  
Polarographic Wave ◽  
Rate Determining Step ◽  
Tafel Slopes ◽  
Reaction Orders ◽  
Mercury Electrodes ◽  
The Waves

The electroreduction of niazid on mercury electrodes has been studied in acidic media (pH < 6). Tafel slopes and reaction orders were obtained at potentials corresponding to the foot of the first polarographic wave. On the basis of both polarographic and voltammetric results it has been shown that the waves appearing at more negative potentials correspond to the reduction of nicotinamide. Protonation of niazid plays an essential role in its reduction and pK values of 1.4, 3.2 and 11.5 were obtained by UV spectroscopy. The process corresponding to the first wave is irreversible, being the second one-electron transfer the rate determining step. Above pH 4 the process is complex due to the overlapping of the waves caused by the occurrence of protonation reactions.

scholarly journals The effects of the chemical environment of menaquinones in lipid monolayers on mercury electrodes on the thermodynamics and kinetics of their electrochemistry

2021 ◽  
Author(s):  
Karuppasamy Dharmaraj ◽  
Dirk Dattler ◽  
Heike Kahlert ◽  
Uwe Lendeckel ◽  
Felix Nagel ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Rate Constants ◽  
Transfer Rate ◽  
Chemical Environment ◽  
Lipid Monolayers ◽  
Redox Potentials ◽  
Electron Transfer Rate ◽  
Thermodynamics And Kinetics ◽  
Mercury Electrodes ◽  
Kinetics Of

AbstractThe effects of the chemical environment of menaquinones (all-trans MK-4 and all-trans MK-7) incorporated in lipid monolayers on mercury electrodes have been studied with respect to the thermodynamics and kinetics of their electrochemistry. The chemical environment relates to the composition of lipid films as well as the adjacent aqueous phase. It could be shown that the addition of all-trans MK-4 to TMCL does not change the phase transition temperatures of TMCL. In case of DMPC monolayers, the presence of cholesterol has no effect on the thermodynamics (formal redox potentials) of all-trans MK-7, but the kinetics are affected. Addition of an inert electrolyte (sodium perchlorate; change of ionic strength) to the aqueous phase shifts the redox potentials of all-trans MK-7 only slightly. The formal redox potentials of all-trans MK-4 were determined in TMCL and nCL monolayers and found to be higher in nCL monolayers than in TMCL monolayers. The apparent electron transfer rate constants, transfer coefficients and activation energies of all-trans MK-4 in cardiolipins have been also determined. Most surprisingly, the apparent electron transfer rate constants of all-trans MK-4 exhibit an opposite pH dependence for TMCL and nCL films: the rate constants increase in TMCL films with increasing pH, but in nCL films they increase with decreasing pH. This study is a contribution to understand environmental effects on the redox properties of membrane bond redox systems. Graphical abstract

Heterogeneous electron-transfer rate measurements of cytochrome c3 at mercury electrodes

1991 ◽  
Vol 297 (1) ◽  
pp. 271-282 ◽  
Author(s):  
Takamasa Sagara ◽  
Shinsuke Nakajima ◽  
Hideo Akutsu ◽  
Katsumi Niki ◽  
George S. Wilson
Keyword(s):  
Electron Transfer ◽  
Transfer Rate ◽  
Electron Transfer Rate ◽  
Cytochrome C3 ◽  
Heterogeneous Electron Transfer ◽  
Mercury Electrodes

Double-Layer Correction for Electron-Transfer Kinetics at Glassy Carbon and Mercury Electrodes inN,N-Dimethylformamide

2006 ◽  
Vol 18 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Ana Belèn Meneses ◽  
Sabrina Antonello ◽  
Maria Carmen Arévalo ◽  
Flavio Maran
Keyword(s):  
Electron Transfer ◽  
Double Layer ◽  
Glassy Carbon ◽  
Electron Transfer Kinetics ◽  
Mercury Electrodes

Interfacial interactions and the heterogeneous one-electron reduction of methyl viologen

1987 ◽  
Vol 52 (5) ◽  
pp. 1097-1114 ◽  
Author(s):  
Michael Heyrovský ◽  
Ladislav Novotný
Keyword(s):  
Electron Transfer ◽  
Radical Cation ◽  
Electrode Surface ◽  
Methyl Viologen ◽  
Potential Range ◽  
Standard Redox Potential ◽  
Mercury Electrodes ◽  
Electron Reduction ◽  
The One ◽  
Surface Redox

The one-electron reversible electroreduction of methyl viologen to its radical cation in aqueous solutions on mercury electrodes proceeds, according to potential, concentration and time of electrolysis, in various ways. Methyl viologen is adsorbed in flat orientation at the electrode surface; it undergoes a surface redox process in π-interaction with the metal in a potential range positive by about 0.2 V of the beginning of the electroreduction. The actual reduction starts by electron transfer followed by adsorption of the radical cation and, at higher concentrations and in a narrow potential range, by crystallization at the electrode surface of a salt of the radical cation. In solution near the electrode the radical cation dimerizes and the dimer also adsorbs at the electrode. In the region of the standard redox potential and more negative the reduction proceeds by electron transfer from the electrode covered by a layer of the radical cation or of its dimer.

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