• Title/Summary/Keyword: Electrochemistry

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Interaction between UN and CdCl2 in molten LiCl-KCl eutectic. II. Experiment at 1023 K

  • Zhitkov, Alexander;Potapov, Alexei;Karimov, Kirill;Kholkina, Anna;Shishkin, Vladimir;Dedyukhin, Alexander;Zaykov, Yury
    • Nuclear Engineering and Technology
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    • v.54 no.2
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    • pp.653-660
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    • 2022
  • The interaction between UN and CdCl2 in the LiCl-KCl molten eutectic was studied at 1023 K. The chlorination was monitored by sampling and recording the redox potential of the medium. At 1023 K the chlorination of UN with cadmium chloride in the molten LiCl-KCl eutectic proceeds completely and results in the formation of uranium chlorides. The melts of the LiCl-KCl-UCl3 or LiCl-KCl-UCl4 compositions can be obtained by the end of experiment depending on the presence of metallic cadmium in the reaction zone. The higher the concentration of the chlorinating agent, the faster the reaction rate. At [CdCl2]/[UN] = 1.65 (10% excess) the reaction proceeds to completion in about 7.5 h. At [CdCl2]/[UN] = 7 the complete chlorination takes 2.5-3 h.

A study of thermolysis of irradiated diamide-containing extraction systems with nitric acid

  • Srvortsov, I.V.;Belova, E.V.;Sokolov, I.P.;Rodin, A.V.;Stefanovsky, S.V.;Mysoedov, B.F.
    • Nuclear Engineering and Technology
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    • v.50 no.8
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    • pp.1421-1425
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    • 2018
  • The dynamics of gas release at thermal oxidation of extraction systems on the basis of diamides of dicarbonic acids in fluorinated sulphones with 14 mol/L $HNO_3$ was investigated. The effect of preirradiation of the mixtures with accelerated electrons on the kinetics of their thermolysis was determined. The mixtures were heated in an autoclave at temperatures of 170 and $200^{\circ}C$ and irradiated using an electron accelerator to absorbed doses of 0.1, 0.5, and 1.0 MGy. It has been shown that no conditions for autocatalytic oxidation at thermolysis of extraction mixtures irradiated up to a dose of 1 MGy were developed.

Fundamentals of Underpotential Deposition : Importance of Underpotential Deposition in Interfacial Electrochemistry

  • Lee Jong-Won;Pyun Su-Il
    • Journal of the Korean Electrochemical Society
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    • v.4 no.4
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    • pp.176-181
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    • 2001
  • This article covers the fundamentals of underpotential deposition (UPD), focussing on the importance of UPD in interfacial electrochemistry. Firstly, this article described the basic concepts of UPD, including underpotential shift and electrosorption valency. Secondly, the present article explained UPD of hydrogen, followed by hydrogen evolution or hydrogen absorption, giving special attention to the adsorption sites of hydrogen on metal surface and the absorption mechanism into Pd. Finally, this article briefly presented the important factors associated with UPD in various fields of interfacial electrochemistry from practical viewpoints.

An Electrochemical Sensor for Hydrazine Based on In Situ Grown Cobalt Hexacyanoferrate Nanostructured Film

  • Kang, Inhak;Shin, Woo-seung;Manivannan, Shanmugam;Seo, Yeji;Kim, Kyuwon
    • Journal of Electrochemical Science and Technology
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    • v.7 no.4
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    • pp.277-285
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    • 2016
  • There is a growing demand for simple, cost-effective, and accurate analytical tools to determine the concentrations of biological and environmental compounds. In this study, a stable electroactive thin film of cobalt hexacyanoferrate (Cohcf) was prepared as an in situ chemical precipitant using electrostatic adsorption of $Co^{2+}$ on a silicate sol-gel matrix (SSG)-modified indium tin oxide electrode pre-adsorbed with $[Fe(CN)_6]^{3-}$ ions. The modified electrode was characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical techniques. Electrocatalytic oxidation of hydrazine on the modified electrode was studied. An electrochemical sensor for hydrazine was constructed on the SSG-Cohcf-modified electrode. The oxidation peak currents showed a linear relationship with the hydrazine concentration. This study provides insight into the in situ growth and stability behavior of Cohcf nanostructures and has implications for the design and development of advanced electrode materials for fuel cells and sensor applications.

Concurrent Electrocatalysis and Sensing of Hydrazine and Sulfite and Nitrite Ions using Electrodeposited Gold Nanostructure-Modified Electrode

  • Seo, Yeji;Manivannan, Shanmugam;Kang, Inhak;Shin, Woo-Seung;Kim, Kyuwon
    • Journal of Electrochemical Science and Technology
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    • v.8 no.1
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    • pp.25-34
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    • 2017
  • Concurrent electrocatalysis and sensing of hydrazine, sulfite ions, and nitrite ions in a mixture were studied using electrodes modified by electrodeposited Au nanostructures (NSs). The ${\beta}$-cyclodextrin-mixed silicate sol-gel composite was drop-casted on the electrode surface and nucleation guided by ${\beta}$-cyclodextrin occurred, followed by the electrodeposition of Au NSs. The additive, ${\beta}$-cyclodextrin, played an evident role as a structure-directing agent; thus, small raspberry-like Au NSs were obtained. The modified electrodes were characterized by surface characterization techniques and electrochemical methods. The Au NSs-modified electrodes effciently electrocatalyzed the oxidation of toxic molecules such as hydrazine and sulfite and nitrite ions even in the absence of any other electron transfer mediator or enzyme immobilization. Well-resolved oxidation peaks along with decreased overpotentials were noticed during the electrooxidation process. The fabricated Au nanostructured electrode clearly distinguished the electrooxidation peaks of each of the three analytes from their mixture.