Irreversible and Reversible Redox Reactions: Water Window

2014 ◽  
pp. 11-16
Author(s):  
Naser Pour Aryan ◽  
Hans Kaim ◽  
Albrecht Rothermel
Keyword(s):  
Redox Reactions ◽  
Water Window ◽  
Reversible Redox

scholarly journals Ultralong π-Conjugated Bis(terpyridine)metal Polymer Wires Covalently Bound to a Carbon Electrode: Fast Redox Conduction and Redox Diode Characteristics

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4267
Author(s):  
Kuo-Hui Wu ◽  
Ryota Sakamoto ◽  
Hiroaki Maeda ◽  
Eunice Jia Han Phua ◽  
Hiroshi Nishihara
Keyword(s):  
Metal Complex ◽  
Electrochemical Method ◽  
Redox Reactions ◽  
Cyclic Voltammograms ◽  
Wire Arrays ◽  
Reversible Redox ◽  
Complex Linear ◽  
Complex Polymer ◽  
Metal Polymer ◽  
Hclo4 Solution

We developed an efficient and convenient electrochemical method to synthesize π-conjugated redox metal-complex linear polymer wires composed of azobenzene-bridged bis(terpyridine)metal (2-M, M = Fe, Ru) units covalently immobilized on glassy carbon (GC). Polymerization proceeds by electrochemical oxidation of bis(4′-(4-anilino)-2,2′:6′,2″-terpyridine)metal (1-M) in a water–acetonitrile–HClO4 solution, affording ultralong wires up to 7400 mers (corresponding to ca. 15 μm). Both 2-Fe and 2-Ru undergo reversible redox reactions, and their redox behaviors indicate remarkably fast redox conduction. Anisotropic hetero-metal-complex polymer wires with Fe and Ru centers are constructed via stepwise electropolymerization. The cyclic voltammograms of two hetero-metal-complex polymer wires, GC/[2-Fe]–[2-Ru] (3) and GC/[2-Ru]–[2-Fe] (4), show irreversible redox reactions with opposite electron transfer characteristics, indicating redox diodelike behavior. In short, the present electrochemical method is useful to synthesize polymer wire arrays and to integrate functional molecules on carbon.

Thermo-chemical water splitting: Selection of priority reversible redox reactions by multi-attribute decision making

2021 ◽  
Vol 170 ◽  
pp. 800-810
Author(s):  
Yimin Deng ◽  
Raf Dewil ◽  
Lise Appels ◽  
Shuo Li ◽  
Jan Baeyens ◽  
...  
Keyword(s):  
Decision Making ◽  
Water Splitting ◽  
Redox Reactions ◽  
Reversible Redox ◽  
Multi Attribute Decision Making ◽  
Chemical Water ◽  
Selection Of

Reversible Redox Reactions in an Extended Polyoxometalate Framework Solid

2008 ◽  
Vol 47 (36) ◽  
pp. 6881-6884 ◽  
Author(s):  
Chris Ritchie ◽  
Carsten Streb ◽  
Johannes Thiel ◽  
Scott G. Mitchell ◽  
Haralampos N. Miras ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Reversible Redox

scholarly journals Electron Inventory of the Iron-Sulfur Scaffold Complex HypCD Essential in [NiFe]-Hydrogenase Cofactor Assembly

2021 ◽  
Author(s):  
Sven T. Stripp ◽  
Jonathan Oltmanns ◽  
Christina S. Müller ◽  
David Ehrenberg ◽  
Ramona Schlesinger ◽  
...  
Keyword(s):  
Redox Reactions ◽  
Redox Activity ◽  
Construction Site ◽  
Iron Ion ◽  
Paramagnetic Resonance ◽  
Iron Sulfur ◽  
Reducing Conditions ◽  
Reversible Redox ◽  
Electron Paramagnetic ◽  
Redox Conversion

The [4Fe-4S] cluster containing scaffold complex HypCD is the central construction site for the assembly of the [Fe](CN)2CO cofactor precursor of [NiFe]-hydrogenase. While the importance of the HypCD complex is well established, not much is known about the mechanism by which the CN– and CO ligands are transferred and attached to the iron ion. We developed an efficient protocol for the production and isolation of the functional HypCD complex that facilitated detailed spectroscopic investigations. The results obtained by UV/Vis-, electron paramagnetic Resonance (EPR)-, Resonance Raman-, Fourier-transform infrared (FTIR), and Mössbauer spectroscopy provide comprehensive evidence for an electron inventory fit to drive multi-electron redox reactions. We demonstrate the redox activity of the HypCD complex reporting the interconversion of the [4Fe-4S]2+/+ couple. Additionally, we observed a reversible redox conversion between the [4Fe-4S]2+ and a [3Fe-4S]+ cluster. MicroScale thermophoresis indicated preferable binding between the HypCD complex and its interaction partner HypEF under reducing conditions. Together, these results suggest a redox cascade involving the [4Fe-4S] cluster and a conserved disulfide bond of HypD that may facilitate the synthesis of the [Fe](CN)2CO cofactor precursor on the HypCD scaffold complex.

A Stable Thin Film from Soluble Single-Walled Carbon Nanotubes on ITO

2011 ◽  
Vol 287-290 ◽  
pp. 2443-2446
Author(s):  
Su Min Wang ◽  
Qi Guan Wang ◽  
Jian Ping Li ◽  
Hiroshi Moriyama ◽  
Wei Xing Chen
Keyword(s):  
Carbon Nanotubes ◽  
Redox Reactions ◽  
Conductive Polymer ◽  
Stable State ◽  
Single Walled Carbon Nanotubes ◽  
Organic Media ◽  
Covalent Bonds ◽  
Single Walled Carbon ◽  
Reversible Redox ◽  
Walled Carbon Nanotubes

Thin films of single-walled carbon nanotubes (SWNTs) attached to an ITO surface (SAM–ITO) self-assembled in advance from 3-aminopropyltrimethoxysilane through amide covalent bonds were prepared. The SWNTs were safely obtained via a two-step process assisted by microwave radiation, which were soluble in aqueous and organic media. However, the CV behavior of SAM–ITO in acidic aqueous systems showed unexpected oxidation signals due to redox reactions involving the defects and sidewalls of soluble functionalized SWNTs. It was found that, after a conductive polymer of polyaniline was chemically incorporated onto the surface of the SWNTs by using electropolymerization method, the CV data showed a single reversible redox couple, which indicated a more stable state.

scholarly journals Pseudocapacitive behavior of the Fe2O3 anode and its contribution to high reversible capacity in lithium ion batteries

Nanoscale ◽  
2018 ◽  
Vol 10 (37) ◽  
pp. 18010-18018 ◽  
Author(s):  
Yimo Xiang ◽  
Zhigao Yang ◽  
Shengping Wang ◽  
Md. Shahriar A. Hossain ◽  
Jingxian Yu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Oxide ◽  
Lithium Ion Batteries ◽  
Redox Reactions ◽  
Lithium Ion ◽  
Transition Metal Oxide ◽  
Reversible Capacity ◽  
High Reversible Capacity ◽  
Reversible Redox ◽  
Pseudocapacitive Behavior

Pseudocapacitance, which is the storage of charge based on continuous and fast reversible redox reactions at the surface of the electrodes, is commonly observed in transition metal oxide based LIB anodes.

A Critical Evaluation of the Redox Properties of Uranium, Neptunium and Plutonium Ions in Acidic Aqueous Solutions

1999 ◽  
Vol 71 (9) ◽  
pp. 1771-1807 ◽  
Author(s):  
Sorin Kihara ◽  
Zenko Yoshida ◽  
Hisao Aoyagi ◽  
Kohji Maeda ◽  
Osamu Shirai ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Redox Reactions ◽  
Critical Evaluation ◽  
Redox Properties ◽  
Redox Processes ◽  
Redox Potentials ◽  
Electrode Processes ◽  
Reversible Redox ◽  
Reduction Mechanisms ◽  
Current Potential

Standard redox potentials, E0s, and redox processes of U, Np and Pu ions in acidic aqueous solutions are reviewed and evaluated critically. The E0sof reversible redox processes, MO22+/MO2+ and M4+/M3+ (M: U, Np or Pu) adopted are those proposed mainly by Riglet et al. on the basis of the precise correction of formal potentials, E0's, according to the improved theoretical approach to estimate the activity coefficient. Electrode processes of the U, Np and Pu ions are discussed in terms of current-potential curves, measured so far by polarography, voltammetry or flow coulometry. Special attention is payed to the irreversible MO2+/M4+ reactions. Disproportionation reactions of MO2+ are also discussed. New substances are introduced as intermediates during reductions of MO2+ to M4+ or disproportionations of MO2+.CONTENTSIntroductionStandard redox potentials for uranium, neptunium and plutonium ions in acidic aqueous solutions2.1 Evaluation of E0 from E0' determined by electrochemical measurements2.2 Temperature dependence of E0Redox reactions of uranium, neptunium and plutonium in acidic aqueous solutions investigated by polarography or voltammetry3.1 Uranium3.2 Neptunium3.3 Plutonium3.4 Disproportionation of NpO2+, PuO2+, Np4+ and Pu4+3.5 Reduction of MO2+ and reduction intermediatesRedox reactions of uranium, neptunium and plutonium in acidic aqueous solutions investigated by flow coulometry4.1 Electrode processes of the uranium, neptunium and plutonium ions investigated by flow coulometry at the column electrode at the column electrode4.2 Disproportionation of MO2+ during the electrolysis by flow coulometry4.3 Reduction mechanisms of MO2+ (M = Np or Pu) and reduction intermediates investigated by flow coulometryConclusionsList of abbreviationsAppendixReferences

Quinone/hydroquinone redox couple as a source of enormous capacitance of activated carbon electrodes

2013 ◽  
Vol 1505 ◽  
Author(s):  
Krzysztof Fic ◽  
Mikolaj Meller ◽  
Grzegorz Lota ◽  
Elzbieta Frackowiak
Keyword(s):  
Activated Carbon ◽  
Redox Reactions ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Hydroxyl Group ◽  
Carbon Surface ◽  
Carbon Electrodes ◽  
Main Subject ◽  
Solution Ph ◽  
Reversible Redox

ABSTRACTThe main subject of this paper is to examine and to evaluate the capacitive behaviour of activated carbon electrodes electrochemically decorated by quinone-type functional groups. For this purpose, different electrolytes, i.e. hydroquinone, catechol and resorcinol at the concentration of 0.38 mol L-1, dissolved in 1 mol L-1 H2SO4, 1 mol L-1 Li2SO4 and 6 mol L-1 KOH were used. These electrolytes could generate electroactive groups (able to undergo reversible redox reactions) on the surface of electrode material. Apart from typical adsorption of the mentioned dihydroxybenzenes, so called grafting could occur and might cause generation of quinone|hydroquinone functionals on carbon surface. As an effect of functional reversible redox reaction, additional capacitance value, called pseudocapacitance, could be achieved. Hence, besides typical charge originating from charging/discharging of the electrical double layer on the electrode/electrolyte interface, additional capacitance comes also from faradaic reactions. Activated carbons are the most promising electrode materials for this purpose; apart from great physicochemical properties, they are characterized by well-developed specific surface area over 2000 m2 g-1 which results in high capacitance values.In the manuscript the influence of the hydroxyl group location as well as electrolyte solution pH on the electrochemical performance of the electrode is discussed.

Theoretical Analysis of Pulse and Differential Pulse Polarography of Reversible Redox Reaction Complicated by Reactant Adsorption

2001 ◽  
Vol 66 (3) ◽  
pp. 423-433 ◽  
Author(s):  
Milivoj Lovrić ◽  
Marina Zelić ◽  
Šebojka Komorsky-Lovrić
Keyword(s):  
Theoretical Analysis ◽  
Redox Reactions ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Peak Width ◽  
Bulk Concentration ◽  
Peak Potential ◽  
Pulse Polarography ◽  
Reversible Redox ◽  
Spherical Diffusion

Pulse and differential pulse polarograms of redox reactions complicated by reactant adsorption with and without lateral attractions in the monolayer are analysed theoretically by using a stationary spherical diffusion model. The continuous shift of the post-peak potential to lower values and the decrease in its half-peak width with increasing bulk concentration of reactant indicate attractions between adsorbed ions or molecules.

Electrochemical Charge Storage Performance of Mesoporous MoO3@Co3O4 Nanocomposites as Electrode Materials

2021 ◽  
Author(s):  
Dillip Kumar Mohapatra ◽  
Swetapadma Praharaj ◽  
Dibyaranjan Rout
Keyword(s):  
Redox Reactions ◽  
High Performance ◽  
Electrode Materials ◽  
Coulombic Efficiency ◽  
Average Pore Size ◽  
Electrochemical Capacitors ◽  
Bet Surface Area ◽  
Average Pore ◽  
Storage Performance ◽  
Reversible Redox

Abstract Constructing a novel nanocomposite structure based on Co3O4 is of the current interest to design and develop efficient electrochemical capacitors. The capacitive performance of MoO3@Co3O4 nanocomposite is compared with pristine Co3O4 nanoparticles, both of them being synthesized by hydrothermal technique. A BET surface area of ~41 m2g-1 (almost twice that of Co3O4 )and average pore size of 3.6 nm is found to be suitable for promoting Faradaic reactions in the nanocomposite. Electrochemical measurements conducted on both samples predict capacitive behavior with quasi-reversible redox reactions. MoO3@Co3O4 nanocomposite is capable of delivering a superior specific capacitance of 1248 Fg-1 at 0.5 Ag-1 along with notable stability of 92% even after 2000 cycles of charge-discharge and Coulombic efficiency approaching 100% at 10 Ag-1. The outstanding results obtained in this work assure functional adequacy of MoO3@Co3O4 nanocomposite in fabricating high-performance electrochemical capacitors.

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