• Title/Summary/Keyword: Electrochemical oxidation

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A Kinetic Investigation of Ethanol Oxidation on a Nickel Oxyhydroxide Electrode

  • Danaee, I.;Jafarian, M.;Sharafi, M.;Gobal, F.
    • Journal of Electrochemical Science and Technology
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    • v.3 no.1
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    • pp.50-56
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    • 2012
  • Nickel modified NiOOH electrodes were used for the electrocatalytic oxidation of ethanol in alkaline solutions where the methods of cyclic voltammetry (CV) and chronoamperometry (CA) were employed. In CV studies, in the presence of ethanol, an increase in the current for the oxidation of nickel hydroxide is followed by a decrease in the corresponding cathodic current. This suggests that the oxidation of ethanol is being catalysed through mediated electron transfer across the nickel hydroxide layer comprising of nickel ions of various valence states. Under the CA regime the reaction followed a Cottrellian behavior and the diffusion coefficient of ethanol was found to be $1{\times}10^7cm^2s^{-1}$.

Formic Acid Oxidation Depending on Rotating Speed of Smooth Pt Disk Electrode

  • Shin, Dongwan;Kim, Young-Rae;Choi, Mihwa;Rhee, Choong Kyun
    • Journal of Electrochemical Science and Technology
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    • v.5 no.3
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    • pp.82-86
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    • 2014
  • This work presents the variation of formic acid oxidation on Pt depending on hydrodynamic condition using a rotating disk electrode. As the rotating speed increases, the oxidation rate of formic acid decreases under voltammetric and chronoamperometric measurements. The coverages of poison formed from formic acid during the chronoamperomertric investigations decrease when the rotating speed increases. As the roughness factor of Pt electrode surface increases, on the other hand, the current density of formic acid oxidation increases. These observations are discussed in terms of the tangential flow along Pt electrode surfaces generated by the rotating disk electrode, which reduces a contact time between formic acid and a Pt site, thus the formic acid adsorption.

Voltammetric Studies of Guanine and Its Derivatives by (TEX)$Ru(bpy)^{2+/3+}$(/TEX) Mediator on Indium Tin Oxide Electrode

  • Kim, Jin Hyeong
    • Bulletin of the Korean Chemical Society
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    • v.21 no.7
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    • pp.709-711
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    • 2000
  • Oxidizing metal complex mediates the electrochemical oxidation of guanine nucleotides. This catalysis results in an enhancement in cyclic voltammograms that yield the rate constant for the oxidation of guanine by the metal complex via digital simulation. The rate constant of oxidation of guanine by Ru(bpy)3(3+) is 6.4 x 10(5)M(-1)s(-l). The rate constant and the enhanced current depend on the number of phosphate groups on the sugar of nucleotidc. Also the modified guanine bases show different oxidation rate constants following the trend guanine-5'- monophosphatc (GMP) > 8-bromo-guanine-5'-monophosphate (8-Br-GMP) > xanthosine -5'-monophosphate (XMP) > inosinc-5'-monophosphate (IMP). The guanine bases derivatized differently are all distinguishable from one another, providing a basis for studying electrochemistry of DNA and RNA and developing electrochemical biosensors.

Electrochemical Reactions of $C_{60}$ Films in the Presence of Water : An Electrochemical Quartz Crystal Microbalance Study

  • 서경자;신명순;전일철
    • Bulletin of the Korean Chemical Society
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    • v.17 no.9
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    • pp.781-786
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    • 1996
  • Mass transport behavior of C60 films on electrodes with different thicknesses has been studied by an Electrochemical Quartz Crystal Microbalance (EQCM) during electrochemical reduction-oxidation processes in the presence of water. C60 films were found to be reduced in the presence of water and they remains quite stable. In thin films, the mass on electrode decreased after a complete cycle while X-ray Photoelectron Spectroscopy (XPS) study does not support the existence or formation of C60-epoxides during electrochemical reduction processes in the presence of water or oxygen.

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.

The Trends in Methanol Oxidation Reaction Mechanisms and Electrochemical Oxidation Catalysts (메탄올 산화 반응 메커니즘과 전기화학 산화 촉매 최신 동향)

  • Sungyool Bong
    • Applied Chemistry for Engineering
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    • v.35 no.2
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    • pp.79-84
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    • 2024
  • Methane is an abundant and renewable hydrocarbon, but it causes global warming as a greenhouse gas. Therefore, methods to convert methane into useful chemicals or energy sources are needed. Methanol is a simple and abundant chemical that can be synthesized by the partial oxidation of methane. Methanol can be used as a chemical feedstock or a transportation fuel, as well as a fuel for low-temperature fuel cells. However, the electrochemical oxidation of methanol is a complex and multi-step reaction. To understand and optimize this reaction, new electrocatalysts and reaction mechanisms are required. This review discusses the methanol oxidation reaction mechanism, recent research trends, and future research directions.

Molybdenum-Based Electrocatalysts for Direct Alcohol Fuel Cells: A Critical Review

  • Gaurav Kumar Yogesh;Rungsima Yeetsorn;Waritnan Wanchan;Michael Fowler;Kamlesh Yadav;Pankaj Koinkar
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.67-95
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    • 2024
  • Direct alcohol fuel cells (DAFCs) have gained much attention as promising energy conversion devices due to their ability to utilize alcohol as a fuel source. In this regard, Molybdenum-based electrocatalysts (Mo-ECs) have emerged as a substitution for expensive Pt and Ru-based co-catalyst electrode materials in DAFCs, owing to their unique electrochemical properties useful for alcohol oxidation. The catalytic activity of Mo-ECs displays an increase in alcohol oxidation current density by several folds to 1000-2000 mA mgPt-1, compared to commercial Pt and PtRu catalysts of 10-100 mA mgPt-1. In addition, the methanol oxidation peak and onset potential have been significantly reduced by 100-200 mV and 0.5-0.6 V, respectively. The performance of Mo-ECs in both acidic and alkaline media has shown the potential to significantly reduce the Pt loading. This review aims to provide a comprehensive overview of the bifunctional mechanism involved in the oxidation of alcohols and factors affecting the electrocatalytic oxidation of alcohol, such as synthesis method, structural properties, and catalytic support materials. Furthermore, the challenges and prospects of Mo-ECs for DAFCs anode materials are discussed. This in-depth review serves as valuable insight toward enhancing the performance and efficiency of DAFC by employing Mo-ECs.