scholarly journals Investigation of the Diffusion Impedance for an Irreversible Redox Reaction

2021 ◽  
pp. ArticleID:210639
Author(s):  
M Chitra Devi ◽  
Keyword(s):  
Redox Reaction ◽  
Diffusion Impedance

scholarly journals Impedance aspect of charge storage at graphite and glassy carbon electrodes in potassium hexacyanoferrate (II) redox active electrolyte

2016 ◽  
Vol 6 (1) ◽  
pp. 37 ◽  
Author(s):  
Katja Magdić ◽  
Višnja Horvat-Radošević ◽  
Krešimir Kvastek
Keyword(s):  
Glassy Carbon ◽  
Redox Reaction ◽  
Supporting Electrolyte ◽  
Carbon Electrodes ◽  
Charge Storage ◽  
Potassium Hexacyanoferrate ◽  
Impedance Spectra ◽  
Glassy Carbon Electrodes ◽  
Redox Active ◽  
Diffusion Impedance

<p class="PaperAbstract"><span lang="EN-GB">Different types of charge storage mechanisms at unmodified graphite vs. glassy carbon electrodes in acid sulphate supporting solution containing potassium hexacyanoferrate (II) redox active electrolyte, have been revealed by electrochemical impedance spectroscopy and supported by cyclic voltammetry experiments. Reversible charge transfer of Fe(CN)6<sup>3-/4-</sup> redox reaction detected by assessment of CVs of glassy carbon electrode, is in impedance spectra indicated by presence of bulk diffusion impedance and constant double-layer/pseudocapacitive electrode impedance compared to that measured in the pure supporting electrolyte. Some surface retention of redox species detected by assessment of CVs of graphite electrode is in impedance spectra indicated by diffusion impedance coupled in this case by diminishing of double-layer/pseudo­capacitive impedance compared to that measured in the pure supporting electrolyte. This phenomenon is ascribed to contribution of additional pseudocapacitive impedance generated by redox reaction of species confined at the electrode surface.</span></p>

Non-Cottrell Behavior of the Dopamine Redox Reaction Observed on the Carbon Fibre Microelectrode by the Double-Step Voltcoulometry

2004 ◽  
Vol 69 (2) ◽  
pp. 419-425 ◽  
Author(s):  
Katarína Gmucová ◽  
Jozef Orlický ◽  
Juraj Pavlásek
Keyword(s):  
Carbon Fibre ◽  
Redox Reaction ◽  
Measured Data ◽  
The Other ◽  
Diffusion Current ◽  
Double Step ◽  
Dopamine Concentration ◽  
Living Body ◽  
Carbon Fibre Microelectrode ◽  
Experimental Errors

The redox reaction of the neurotransmitter dopamine at the carbon fibre microelectrode was studied by several electrochemical methods. It was found that under conditions usual in a living body, the diffusion current fullfils, within experimental errors, the behavior theoretically predicted by the Cottrell equation. Nevertheless, attention should be paid to the fact that unsupported or weakly supported conditions give rise to a non-Cottrell response of diffusion current. Moreover, similar changes were observed if the dopamine concentration was either lower such as several units of μmol l-1, or about 100 μmol l-1 or higher. The non-Cottrell behavior of diffusion current involves the nonlinearity of the dopamine calibration curve obtained by pulse techniques. The present work is aimed at pointing out that such behavior of the measured data could lead to misinterpretation of the obtained dopamine concentration. Similar features could be also achieved for the other catecholamines.

Accelerated Redox Reaction of Hydrogen Peroxide by Employing Locally Concentrated State of Copper Catalysts on Polymer Chain

2021 ◽  
pp. 2100274
Author(s):  
Shigehito Osawa ◽  
Kenichi Kitanishi ◽  
Maho Kiuchi ◽  
Motoyuki Shimonaka ◽  
Hidenori Otsuka
Keyword(s):  
Hydrogen Peroxide ◽  
Polymer Chain ◽  
Redox Reaction ◽  
Copper Catalysts

scholarly journals Thermochemical Energy Storage Performance Analysis of (Fe,Co,Mn)Ox Mixed Metal Oxides

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 362
Author(s):  
Yabibal Getahun Dessie ◽  
Qi Hong ◽  
Bachirou Guene Lougou ◽  
Juqi Zhang ◽  
Boshu Jiang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Metal Oxide ◽  
Metal Oxides ◽  
Redox Reaction ◽  
Gas Flow ◽  
Oxygen Exchange ◽  
Engineering Industry ◽  
Oxide Material ◽  
Oxide Materials ◽  
Uptake Ratio

Metal oxide materials are known for their ability to store thermochemical energy through reversible redox reactions. Metal oxides provide a new category of materials with exceptional performance in terms of thermochemical energy storage, reaction stability and oxygen-exchange and uptake capabilities. However, these characteristics are predicated on the right combination of the metal oxide candidates. In this study, metal oxide materials consisting of pure oxides, like cobalt(II) oxide, manganese(II) oxide, and iron(II, III) oxide (Fe3O4), and mixed oxides, such as (100 wt.% CoO, 100 wt.% Fe3O4, 100 wt.% CoO, 25 wt.% MnO + 75 wt.% CoO, 75 wt.% MnO + 25 wt.% CoO) and 50 wt.% MnO + 50.wt.% CoO), which was subjected to a two-cycle redox reaction, was proposed. The various mixtures of metal oxide catalysts proposed were investigated through the thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy dispersive X-ray (EDS), and scanning electron microscopy (SEM) analyses. The effect of argon (Ar) and oxygen (O2) at different gas flow rates (20, 30, and 50 mL/min) and temperature at thermal charging step and thermal discharging step (30–1400 °C) during the redox reaction were investigated. It was revealed that on the overall, 50 wt.% MnO + 50 wt.% CoO oxide had the most stable thermal stability and oxygen exchange to uptake ratio (0.83 and 0.99 at first and second redox reaction cycles, respectively). In addition, 30 mL/min Ar–20 mL/min O2 gas flow rate further increased the proposed (Fe,Co,Mn)Ox mixed oxide catalyst’s cyclic stability and oxygen uptake ratio. SEM revealed that the proposed (Fe,Co,Mn)Ox material had a smooth surface and consisted of polygonal-shaped structures. Thus, the proposed metallic oxide material can effectively be utilized for high-density thermochemical energy storage purposes. This study is of relevance to the power engineering industry and academia.

Possible high-potential ilmenite type Na1MO3 (M=V–Ni) cathodes realized by dominant oxygen redox reaction

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
M. H. N. Assadi ◽  
Masashi Okubo ◽  
Atsuo Yamada ◽  
Yoshitaka Tateyama
Keyword(s):  
Redox Reaction ◽  
High Potential
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