Accurate Standard Hydrogen Electrode Potential and Applications to the Redox Potentials of Vitamin C and NAD/NADH

2015 ◽  
Vol 119 (2) ◽  
pp. 369-376 ◽  
Author(s):  
Toru Matsui ◽  
Yasutaka Kitagawa ◽  
Mitsutaka Okumura ◽  
Yasuteru Shigeta
Keyword(s):  
Vitamin C ◽  
Electrode Potential ◽  
Standard Hydrogen Electrode ◽  
Redox Potentials ◽  
Hydrogen Electrode

Consistent scheme for computing standard hydrogen electrode and redox potentials

2012 ◽  
Vol 34 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Toru Matsui ◽  
Yasutaka Kitagawa ◽  
Mitsutaka Okumura ◽  
Yasuteru Shigeta ◽  
Shigeyoshi Sakaki
Keyword(s):  
Standard Hydrogen Electrode ◽  
Redox Potentials ◽  
Hydrogen Electrode

Redox properties of MX-80 and Montigel bentonite-water systems

2002 ◽  
Vol 757 ◽  
Author(s):  
Cecilia Lazo ◽  
Ola Karnland ◽  
Eva-Lena Tullborg ◽  
Ignasi Puigdomenech
Keyword(s):  
Dissolved Oxygen ◽  
Pyrite Oxidation ◽  
Water Systems ◽  
Redox Properties ◽  
Membrane Electrode ◽  
Main Process ◽  
Standard Hydrogen Electrode ◽  
Redox Potentials ◽  
Hydrogen Electrode ◽  
Similar Time

ABSTRACTThe uptake of dissolved oxygen (O2) has been studied in bentonite suspensions in 0.1 M NaCl media at (25±2)°C. MX-80 and Montigel bentonites were used in concentrations varying from 18 to 73 g/L. The experiments were performed in a magnetically stirred closed glass vessel, in an N2-glove box. Redox potentials where measured with Pt-wires, and dissolved O2 was measured both with a membrane electrode and with an optode. The experiments with MX-80 show that dissolved O2 disappears in ∼5 days under these conditions. Redox potentials decreased from ∼ +500 to ∼ +125 mVSHE (versus Standard Hydrogen Electrode). The data for the Montigel bentonite show similar time scales for O2 uptake but lower redox potentials at the end of the experiments ∼ −175 mVSHE. Pyrite oxidation is perhaps not the main process for O2 uptake, as MX-80 contains 0.3% FeS2 while Montigel bentonite only has a negligible amount.

scholarly journals Absolute Standard Hydrogen Electrode Potential Measured by Reduction of Aqueous Nanodrops in the Gas Phase

2008 ◽  
Vol 130 (11) ◽  
pp. 3371-3381 ◽  
Author(s):  
William A. Donald ◽  
Ryan D. Leib ◽  
Jeremy T. O'Brien ◽  
Matthew F. Bush ◽  
Evan R. Williams
Keyword(s):  
Gas Phase ◽  
Electrode Potential ◽  
Standard Hydrogen Electrode ◽  
Hydrogen Electrode

scholarly journals The amount of hydrogen and oxygen present on the surface of a metallic electrode

1929 ◽  
Vol 125 (798) ◽  
pp. 446-462 ◽  
Keyword(s):  
Linear Function ◽  
Linear Relation ◽  
Electrode Potential ◽  
Reversible Hydrogen Electrode ◽  
Acid Electrolyte ◽  
Hydrogen Electrode ◽  
Metallic Electrode ◽  
Mercury Surface ◽  
First Approximation ◽  
Accessible Area

In a pervious communication a study has been made of the potential changes which occur during the discharge of small quantities of electricity at metallic cathodes in an acid electrolyte. The electrode potential was, in general, more negative than the reversible hydrogen electrode, and it was found that over this range the potential change was a linear function of the quantity of electricity passed. This quantity was very small, 6 X 10 -7 coulombs per square centimetre causing a change of 100 millivolts in the electrode potential at a mercury surface. This linear relation was found on all the metals investigated, but the quantity varied with the nature and condition of the surface, being greater the rougher the surface. Experiments with amalgams, and platinised mercury surfaces showed that this quantity was, to a first approximation, accessible area of its surface. It was suggested that this change in potential may be regarded as due to the deposition of more hydrogen dipoles to the surface, or alternatively to a flux of electricity across the interface causing a further deformation of the hydrogen dipoles already present on the surface. Although the potential changes accompanying these additions to the surface have been studied, few measurements were made of the quantity of hydrogen initially present on the surface at the reversible hydrogen potential. It was considered probable that this was approximately a monatomic layer but it was of some interest to investigate this point.

scholarly journals Electrochemical, Spectroscopic, and Computational Investigations on Redox Reactions of Selenium Species on Galena Surfaces

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 437 ◽  
Author(s):  
Peter Cook ◽  
YoungJae Kim ◽  
Ke Yuan ◽  
Maria C. Marcano ◽  
Udo Becker
Keyword(s):  
Photoelectron Spectroscopy ◽  
Redox Reactions ◽  
Redox Potentials ◽  
Free Energies ◽  
Cathodic Peak ◽  
Redox Transformation ◽  
Hydrogen Electrode ◽  
Midpoint Potential ◽  
Ph Conditions ◽  
Cv Measurements

Despite previous studies investigating selenium (Se) redox reactions in the presence of semiconducting minerals, Se redox reactions mediated by galena (PbS) are poorly understood. In this study, the redox chemistry of Se on galena is investigated over a range of environmentally relevant Eh and pH conditions (+0.3 to −0.6 V vs. standard hydrogen electrode, SHE; pH 4.6) using a combination of electrochemical, spectroscopic, and computational approaches. Cyclic voltammetry (CV) measurements reveal one anodic/cathodic peak pair at a midpoint potential of +30 mV (vs. SHE) that represents reduction and oxidation between HSeO3− and H2Se/HSe−. Two peak pairs with midpoint potentials of −400 and −520 mV represent the redox transformation from Se(0) to HSe− and H2Se species, respectively. The changes in Gibbs free energies of adsorption of Se species on galena surfaces as a function of Se oxidation state were modeled using quantum-mechanical calculations and the resulting electrochemical peak shifts are (−0.17 eV for HSeO3−/H2Se, −0.07 eV for HSeO3−/HSe−, 0.15 eV for Se(0)/HSe−, and −0.15 eV for Se(0)/H2Se). These shifts explain deviation between Nernstian equilibrium redox potentials and observed midpoint potentials. X-ray photoelectron spectroscopy (XPS) analysis reveals the formation of Se(0) potentials below −100 mV and Se(0) and Se(−II) species at potentials below −400 mV.

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