scholarly journals The Electrochemical Reduction Mechanism of ZnFe2O4 in NaCl-CaCl2 Melts

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 925
Author(s):  
Chang Liu ◽  
Jinglong Liang ◽  
Hui Li ◽  
Hongyan Yan ◽  
Sijia Zheng ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Thermodynamic Analysis ◽  
Irreversible Process ◽  
Gradual Increase ◽  
Reduction Process ◽  
Reduction Mechanism ◽  
Reversible Process ◽  
Electrochemical Tests ◽  
Oxygen Ions ◽  
One Step

The electrochemical reduction process of ZnFe2O4 in NaCl-CaCl2 melts was studied. Thermodynamic analysis shows that the reduction process of ZnFe2O4 is carried out in multiple steps, and it is difficult to reduce Fe3+ to Fe in one step. Electrochemical tests revealed that the reduction process of ZnFe2O4 includes three steps: First, Fe3+ is reduced to Fe in two steps, then Zn2+ is reduced to Zn in one step. The reduction of Fe3+ on the Mo electrode is a reversible process controlled by diffusion, while the reduction of Zn2+ is an irreversible process controlled by diffusion. The influence of electrolysis voltage and temperature on the process of electric deoxidation has also been studied. It is indicated that properly increasing the temperature is conducive to the diffusion of oxygen ions, thereby increasing the deoxidation rate. With the gradual increase of voltage, the reduction process of ZnFe2O4 is ZnFe2O4 → FeO + ZnO → Fe + ZnO → Fe + Zn.

scholarly journals Electrochemical reduction mechanism of several oxides of refractory metals in FClNaKmelts

2020 ◽  
Vol 39 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Hui Li ◽  
Lei Jia ◽  
Jing Wang ◽  
Jing-long Liang ◽  
Hong-yan Yan ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electrochemical Reduction ◽  
Chemical Reaction ◽  
Transfer Process ◽  
Reduction Process ◽  
Refractory Metals ◽  
Reduction Mechanism ◽  
Reversible Process ◽  
Electron Transfer Process ◽  
One Step

AbstractThe dissolution characteristics and electrochemical reduction mechanism of oxides of refractory metals ZrO2, HfO2 and MoO3 in NaCl-KCl-NaF melts are studied. The results shows that there are no chemical reaction of ZrO2 and HfO2 in NaCl-KCl-NaF melts, the dissolution of MoO3 is chemically dissolved, and MoO3 reactwith melts to form Na2Mo2O7. The reduction process of zirconium in the NaCl-KCl-NaF-ZrO2 melts is a reversible process of one-step electron transfer controlled by diffusion. The electrochemical reduction process of ruthenium is a one-step reversible process and the product is insoluble; Electrochemical reduction of metallic molybdenum in melts is controlled by the diffusion and electron transfer process of active ion Mo2O27− . The electrochemical reduction process of the metal molybdenum in the melts is carried out in two steps.

Electrochemical reduction of maleic and fumaric acids and their dimethyl esters in methanol at a mercury electrode

1987 ◽  
Vol 52 (9) ◽  
pp. 2132-2141
Author(s):  
Dimitra Sazou ◽  
Pantelis Karabinas
Keyword(s):  
Double Bond ◽  
Electrochemical Reduction ◽  
Mercury Electrode ◽  
Cyclic Voltammograms ◽  
Reduction Mechanism ◽  
Proton Donors ◽  
Carboxylic Groups ◽  
One Step ◽  
Pure Methanol ◽  
Successive Reduction

The electrochemical reduction of maleic and fumaric acids and their dimethyl esters have been investigated by cyclic voltammetry on HMDE in pure methanol. The cyclic voltammograms of the free acids show two successive reduction waves due to the influence of the different strength of the carboxylic groups on the double bond reduction. The reduction mechanism is verified by examining the effect of different supporting electrolytes, proton donors, and strong bases on the reduction waves. The double bond reduction of the corresponding dimethyl esters takes place in one step.

Electroanalytical chemistry of vanadium complexes. Comparison of the voltammetric features of amavadine with those of the vanadium complexes with iminodiacetic acid and methyliminodiacetic acid

1989 ◽  
Vol 54 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Roland Meier ◽  
Harald Frank ◽  
Reinhard Kirmse ◽  
Reiner Salzer ◽  
Joachim Stach ◽  
...  
Keyword(s):  
Iminodiacetic Acid ◽  
Vanadium Complexes ◽  
Reduction Mechanism ◽  
Reversible Process ◽  
Electroanalytical Chemistry ◽  
Probable Explanation ◽  
Chemical Sense ◽  
Ece Mechanism ◽  
Methyliminodiacetic Acid

The voltammetric behaviour of amavadine (AV) was found to be considerably different from that of the complexes of VO2+ with methyliminodiacetic acid (MIDA) and iminodiacetic acid (IDA). To get an insight in the rather complicated reduction mechanism of the latter complexes the reductions of V(III) (MIDA) and V(III) (IDA) have been studied for comparison. The species V(III) (MIDA)2 and V(III) (IDA)2 are reduced to the appropriate V(II) complexes in a chemically reversible process. VO(MIDA)2 and VO(IDA)2 are reduced to the same complexes via an ECE mechanism. The investigation of the electroreduction of AV shows that this process is not reversible in the chemical sense. As a probable explanation, the conclusion was drawn that AV and the usual V(IV)O-iminocarboxylato complexes differ in their structures.

scholarly journals The Carnot Cycle, Reversibility and Entropy

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 810
Author(s):  
David Sands
Keyword(s):  
Irreversible Process ◽  
Entropy Change ◽  
External Pressure ◽  
Step Change ◽  
Equilibrium States ◽  
Rate Equations ◽  
Carnot Cycle ◽  
Work Processes ◽  
Reversible Process ◽  
External Conditions

The Carnot cycle and the attendant notions of reversibility and entropy are examined. It is shown how the modern view of these concepts still corresponds to the ideas Clausius laid down in the nineteenth century. As such, they reflect the outmoded idea, current at the time, that heat is motion. It is shown how this view of heat led Clausius to develop the entropy of a body based on the work that could be performed in a reversible process rather than the work that is actually performed in an irreversible process. In consequence, Clausius built into entropy a conflict with energy conservation, which is concerned with actual changes in energy. In this paper, reversibility and irreversibility are investigated by means of a macroscopic formulation of internal mechanisms of damping based on rate equations for the distribution of energy within a gas. It is shown that work processes involving a step change in external pressure, however small, are intrinsically irreversible. However, under idealised conditions of zero damping the gas inside a piston expands and traces out a trajectory through the space of equilibrium states. Therefore, the entropy change due to heat flow from the reservoir matches the entropy change of the equilibrium states. This trajectory can be traced out in reverse as the piston reverses direction, but if the external conditions are adjusted appropriately, the gas can be made to trace out a Carnot cycle in P-V space. The cycle is dynamic as opposed to quasi-static as the piston has kinetic energy equal in difference to the work performed internally and externally.

Electrochemical tools to disclose the electrochemical reduction mechanism of CO2 in aprotic solvents and ionic liquids

2021 ◽  
pp. 115411
Author(s):  
Silvia Mena ◽  
Esteve Ribas ◽  
Clara Richard ◽  
Iluminada Gallardo ◽  
Jordi Faraudo ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Electrochemical Reduction ◽  
Aprotic Solvents ◽  
Reduction Mechanism

Fabrication of Janus GO/rGO humidity actuator by one-step electrochemical reduction route

2022 ◽  
Vol 354 ◽  
pp. 131198
Author(s):  
Zeriş Aksu ◽  
Cengiz Han Şahin ◽  
Murat Alanyalıoğlu
Keyword(s):  
Electrochemical Reduction ◽  
One Step

Performance of poly-o-phenylenediamine and its carbon dot composite electrode in the removal of Cu2+ from its aqueous solution

2021 ◽  
pp. 2151037
Author(s):  
Yu Meng ◽  
Qing Zhong ◽  
Arzugul Muslim
Keyword(s):  
Aqueous Solution ◽  
Electrochemical Reduction ◽  
Composite Electrode ◽  
Reduction Process ◽  
Order Kinetic ◽  
Carbon Dot ◽  
First Order ◽  
Oxidation Reduction ◽  
Order Kinetic Model ◽  
Optimal Ph

Because −NH2 and −NH− in poly-[Formula: see text]-phenylenediamine (P[Formula: see text]PD) can interact strongly with the empty orbitals of Cu to show unique electrochemical activity, P[Formula: see text]PD is suitable for the removal of Cu[Formula: see text] by electrochemical oxidation–reduction process. In this study, with P[Formula: see text]PD and its carbon dot composite (CDs/P[Formula: see text]PD) as working electrodes, the electrochemical reduction and removal of Cu[Formula: see text] in the aqueous solution were carried out with the potentiostatic method. According to effects of voltage, pH of the solution, initial concentration of Cu[Formula: see text], and electrochemical reduction time on the Cu[Formula: see text] removal, the Cu[Formula: see text] removal ratios of P[Formula: see text]PD and CDs/P[Formula: see text]PD were up to 64.69% and 73.34%, respectively, at −0.2 V and the optimal pH. Additionally, results showed that these processes were in line with the quasi-first order kinetic model. Both P[Formula: see text]PD and CDs/P[Formula: see text]PD showed good reproducibility in six cycles. After five times of repeated usage, the regeneration efficiencies of P[Formula: see text]PD and CDs/P[Formula: see text]PD dropped to 77.04% and 79.36%, respectively.

Production of novel carbon nanostructures by electrochemical reduction of polychlorinated organic rings under mild conditions for supercapacitors

2021 ◽  
Author(s):  
Züleyha Kudaş ◽  
Emir Çepni ◽  
Emre Gür ◽  
Duygu Ekinci
Keyword(s):  
Carbon Source ◽  
Electrochemical Reduction ◽  
Electrochemical Method ◽  
Carbon Nanostructures ◽  
Electrochemical Growth ◽  
Mild Conditions ◽  
One Step ◽  
The One ◽  
Carbon Based

Here, new carbon-based nanostructures were prepared by the one-step electrochemical method using hexagonal and pentagonal polychlorinated organic rings as carbon source. The electrochemical growth of carbon nanostructures on substrates was...

Electrochemical reduction mechanism of camptothecin at glassy carbon electrode

2010 ◽  
Vol 79 (2) ◽  
pp. 173-178 ◽  
Author(s):  
Afzal Shah ◽  
Victor C. Diculescu ◽  
Rumana Qureshi ◽  
Ana Maria Oliveira-Brett
Keyword(s):  
Electrochemical Reduction ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Carbon Electrode ◽  
Reduction Mechanism
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