Search results for "Redox"

Solvent-Independent Electrode Potentials of Solids Undergoing Insertion Electrochemical Reactions: Part III. Experimental Data for Prussian Blue Unde…

2012

Prussian blue-modified electrodes immersed in K+-containing solutions can be used to obtain a solvent-independent redox potential system. On the basis of theoretical modeling of diffusion processes occurring under the conditions of voltammetry of immobilized particles, voltammetric and chronoamperometric data can be combined to obtain solvent-independent electrode potentials for the K+-assisted one-electron reduction of Prussian blue to Berlin white. Data for water, MeOH, EtOH, MeCN, DMS, DMF, and NM are provided.

Improving the onset potential and Tafel slope determination of earth-abundant water oxidation electrocatalysts

2021

To date, a plethora of electrocatalysts for the Oxygen Evolution Reaction (OER) have been proposed. For evaluating their electrocatalytic behavior the determination of the onset potential in each studied electrolyte is a key parameter. Nevertheless, this evaluation becomes particularly problematic for first- transition metal catalysts as well as by the use of electroactive collectors ( e.g. Ni foams) whose redox peaks overlap the onset potential. A usual solution to detect the onset potential requires the availabil- ity of in-situ mass spectrometric determination of the generated oxygen. In this work, we present fast and easier available cyclic voltammetry and coulovoltammetric responses to…

SELECTION OF REDOX SYSTEMS FOR REVERSE ELECTRODIALYSIS PROCESSES

2012

In reverse electrodialysis (RED) processes, electrical energy is directly extracted from chemical potential gradients arising from salinity differences, especially from sea and river water. In RED there are at least four complementary elements: (1) electrodes, where electron transfer reactions occur to allow the transformation of the charge carrier from ion to electron; (2) ion selective exchange membranes, which allow the selective transport of ions; (3) solvents, which make a continuum for ion transport; (4) electrolytes, i.e. the current carriers between cathode and anode. Studies on RED processes were mainly focused on membranes but also on several other aspects including electrolyte co…

Investigation of electrode material - redox couple systems for reverse electrodialysis processes

2012

Age-dependent regulation of antioxidant genes by p38α MAPK in the liver

2018

p38α is a redox sensitive MAPK activated by pro-inflammatory cytokines and environmental, genotoxic and endoplasmic reticulum stresses. The aim of this work was to assess whether p38α controls the antioxidant defense in the liver, and if so, to elucidate the mechanism(s) involved and the age-related changes. For this purpose, we used liver-specific p38α-deficient mice at two different ages: young-mice (4 months-old) and old-mice (24 months-old). The liver of young p38α knock-out mice exhibited a decrease in GSH levels and an increase in GSSG/GSH ratio and malondialdehyde levels. However, old mice deficient in p38α had higher hepatic GSH levels and lower GSSG/GSH ratio than young p38α knock-…

Mechanisms of interference of p-diphenols with the Trinder reaction

2020

p-Diphenols, such as homogentisic acid, gentisic acid, etamsylate, and calcium dobesilate, interfere with diagnostic tests utilizing the Trinder reaction but the mechanisms of these effects are not fully understood. We observed substantial differences both in oxidation of p-diphenols by horseradish peroxidase and their influence on oxidation of 4-aminoantipyrine and various phenolic substrates. Homogentisic acid was rapidly oxidized by the enzyme and completely blocked chromophore formation. Enzymatic oxidation of the remaining p-diphenols was slow and they only moderately inhibited chromophore formation. However, in the presence of standard substrates all tested p-diphenols were rapidly co…

Electrochemical studies on organometallic compounds—xx. Electrogeneration of an unusual organometallic derivative of ruthenium(I)

1989

Abstract The two-electron reduction of dinuclear ruthenium complexes [RuCl 2 (η 6 - p -cymene)] 2 ( p -cymene = p -CH 3 C 6 H 4 CH(CH 3 ) 2 ] give the corresponding relatively stable ruthenium(I) dimer derivative. The same species can also be obtained by electrochemical reduction of the cationic complexes [(η 6 - p -cymene)Ru(μ-Cl) 3 Ru(η 6 - p -cymene)]PF 6 . A redox mechanism is proposed.

Kinetic Study of the Oxidation of n-Butane on Vanadium Oxide Supported on Al/Mg Mixed Oxide

1997

The reaction kinetics of the oxidative dehydrogenation (ODH) of n-butane over vanadia supported on a heat-treated Mg/Al hydrotalcite (37.3 wt % of V2O5) was investigated by both linear and nonlinear regression techniques. A reaction network including the formation of butenes (1-, 2-cis-, and 2-trans-butene), butadiene, and carbon oxides by parallel and consecutive reactions, at low and high n-butane conversions, has been proposed. Langmuir−Hinshelwood (LH) models can be used as suitable models which allows reproduction of the global kinetic behavior, although differences between oxydehydrogenation and deep oxidation reactions have been observed. Thus, the formation of oxydehydrogenation pro…

Coadsorption of NRR and HER Intermediates Determines the Performance of Ru-N4 toward Electrocatalytic N2 Reduction

2021

Efficiency of the electrochemical N2 reduction reaction (NRR) to ammonia is seriously limited by the competing hydrogen evolution reaction (HER) but our current atomic-scale insight on the factors controlling HER/NRR competition are unknown. Herein we unveil the elementary mechanism, thermodynamics, and kinetics determining the HER/NRR selectivity on the state-of-the-art NRR electrocatalyst, Ru-N4 using constant potential density functional theory calculations (DFT). The calculations show that NRR and HER intermediates coadsorb on the catalyst where HER is greatly suppressed by the NRR intermediates. The first reaction step leading to either *NNH or *H determines the selectivity towards NRR…

A chemical and electrochemical multivalent memory made from FeNi3-graphene nanocomposites

2014

FeNi3-graphene nanocomposites present in acetonitrile solutions a redox couple with an electrochemical hysteresis of 2.4 V between the oxidation and the reduction maxima. In view of the high energy required for the reverse transitions, they are here proposed as chemical multilevel memories: permanent, after drying, or erasable in electrolytes, respectively. Keywords: FeNi3-graphene nanocomposites, Voltammetry, Coulovoltammetry, Redox couple, Redox hysteresis