• Title/Summary/Keyword: Spectroelectrochemical

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Review, Assessment, and Learning Lesson on How to Design a Spectroelectrochemical Experiment for the Molten Salt System

  • Killinger, Dimitris;Phongikaroon, Supathorn
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.20 no.2
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    • pp.209-229
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    • 2022
  • This work provided a review of three techniques-(1) spectrochemical, (2) electrochemical, and (3) spectroelectrochemical-for molten salt medias. A spectroelectrochemical system was designed by utilizing this information. Here, we designed a spectroelectrochemical cell (SEC) and calibrated temperature controllers, and performed initial tests to explore the system's capability limit. There were several issues and a redesign of the cell was accomplished. The modification of the design allowed us to assemble, align the system with the light sources, and successfully transferred the setup inside a controlled environment. A preliminary run was executed to obtain transmission and absorption background of NaCl-CaCl2 salt at 600℃. It shows that the quartz cuvette has high transmittance effects across all wavelengths and there were lower transmittance effects at the lower wavelength in the molten salt media. Despite a successful initial run, the quartz vessel was mated to the inner cavity of the SEC body. Moreover, there was shearing in the patch cord which resulted in damage to the fiber optic cable, deterioration of the SEC, corrosion in the connection of the cell body, and fiber optic damage. The next generation of the SEC should attach a high temperature fiber optic patch cords without introducing internal mechanical stress to the patch cord body. In addition, MACOR should be used as the cell body materials to prevent corrosion of the surface and avoid the mating issue and a use of an adapter from a manufacturer that combines the free beam to a fiber optic cable should be incorporated in the future design.

In-Situ Spectroelectrochemical Studies of Manganese(II) Oxidation

  • Zhang, Haiyan;Park, Su-Moon
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.569-574
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    • 1995
  • In-situ spectroelectrochemical studies have been carried out on the oxidation of Mn(II) at platinum, gold, lead dioxide, and bismuth doped lead dioxide electrodes. The Mn(III), $MnO_2$, and/or ${MnO_4}^-$ species are produced depending on experimental conditions employed during electrolysis. Mn(III) is shown to be produced from a very early stage during the anodic potential scan and undergo disproportionation-conproportionation reactions depending on the relative concentration of each species near the electrode surface. An oxidation mechanism consistent with these observations is proposed.

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Real Time Spectroelectrochemical Experiments with a Multichannel Detector

  • Sun-Il Mho;Sally N. Holer;Bum-Soo Kim;Su-Moon Park
    • Bulletin of the Korean Chemical Society
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    • v.15 no.9
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    • pp.739-743
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    • 1994
  • A spectroelectrochemical system assembled with a white light source, bifurcated optical fiber, Oriel Multispec spectrograph, and a charge-coupled device (CCD) detector is described. The system is shown to be capable of acquiring a whole spectrum in the spectral range of 290-800 nm in 25 ms or a longer period during electrochemical experiments at reflective working electrodes such as platinum or mercury. The utility of the system in studying electrochemical reactions during the potential scan, galvanostatic electrolysis, or after the potential step is demonstrated.

Electrochemical and Spectroelectrochemical Behaviors of Vitamin K1/Lipid Modified Electrodes and the Formation of Radical Anion in Aqueous Media

  • Yang, Jee-Eun;Yoon, Jang-Hee;Won, Mi-Sook;Shim, Yoon-Bo
    • Bulletin of the Korean Chemical Society
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    • v.31 no.11
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    • pp.3133-3138
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    • 2010
  • The electrochemical properties of the liposoluble vitamin $K_1$ adsorbed on bare and lipid coated glassy carbon electrodes (GCEs) were studied in unbuffered and well buffered aqueous media. The reduction products of vitamin $K_1$ were characterized by employing cyclic voltammetry and the in situ UV-visible spectroelectrochemical technique. The radical species of vitamin $K_1$ cannot be observed at the bare GCEs in well buffered media. The formation of the anion radical of vitamin $K_1$ was observed in unbuffered solutions above pH 5.9 or at the lipid coated GCE in a well-buffered solution. UV-visible absorption bands of neutral vitamin $K_1$ were observed at 260 nm and 330 nm, and a band corresponding to the anion radical species was observed at 450 nm. The derivative cyclic voltabsorptometric (DCVA) curves obtained for electrochemical reduction of vitamin $K_1$ confirmed the presence of both neutral and anion radical species. The anion radical of vitamin $K_1$ formed at the hydrophobic conditions with phosphatidylcholine (PC) lipid coated electrode was stable enough to be observed in the spectroelectrochemical experiments.

Electrochemical and Spectroelectrochemical Studies of Cobalt Salen and Salophen as Oxygen Reduction Catalysts

  • Bertha Ortiz;Park, Su Mun
    • Bulletin of the Korean Chemical Society
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    • v.21 no.4
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    • pp.405-411
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    • 2000
  • Electrochemical and spectroelectrochemical studies of cobalt-Schiff (Co-SB) base complexes, Co(salen) [N-N'-bis(salicylaldehyde)-ethylenediimino cobalt(II)] and Co(salophen) [N-N'-bis(salicylaldehyde)-1,2-pheny-lenediimino cobalt(II)], have been c arried out to test them as oxygen reduction catalysts. Both compounds were found to form an adduct with oxygen and exhibit catalytic activities for oxygen reduction. Comparison of spec-tra obtained from electrooxidized complexes with those from Co-SB complexes equilibrated with oxygen in-dicates that the latter are consistent with the postulated complex formed with oxygen occupying the coaxial ligand position, namely, Co(III)-SB·O2 - .The catalysis of oxygen reduction is thus achieved by reducing Co(III) in the oxygen-Co-SB adduct, releasing the oxygen reduction product, e.g., O2 - ., from the Co(II)-SB complex.