• 제목/요약/키워드: Electrochemical oxidation

검색결과 685건 처리시간 0.023초

Voltammetric Determination of Bisphenol A Using a Carbon Paste Electrode Based on the Enhancement Effect of Cetyltrimethylammonium Bromide (CTAB)

  • Huang, Wensheng
    • Bulletin of the Korean Chemical Society
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    • 제26권10호
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    • pp.1560-1564
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    • 2005
  • The influence of cetyltrimethylammonium bromide (CTAB) on the electrochemical behavior of bisphenol A at the carbon paste electrode (CPE) was investigated. CTAB, with a hydrophobic C-H chain, can adsorb at the CPE surface via hydrophobic interaction and then change the electrode/solution interface, and finally affects the electrochemical response of bisphenol A, confirming from the remarkable oxidation peak current enhancement. The electrode process of bisphenol A was examined, and then all the experimental parameters which affects the electrochemical response of bisphenol A, such as pH value of the supporting electrolyte, accumulation potential and time, potential scan rate and the concentration of CTAB, were examined. Finally, a sensitive and simple voltammetric method was developed for the determination of bisphenol A. Under the optimum conditions, the oxidation peak current of bisphenol A varied linearly with its concentration over the range from $2.5\;{\times}\;10^{-8}\;to\;1\;{\times}\;10^{-6}$ mol/L, and the detection limit was found to be $7.5\;{\times}\;10^{-9}$ mol/L. This method was successfully employed to determine bisphenol A in some waste plastic samples.

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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    • 제3권1호
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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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    • 제5권3호
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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

  • 김진형
    • Bulletin of the Korean Chemical Society
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    • 제21권7호
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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.

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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    • 제7권4호
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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.

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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    • 제17권9호
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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.

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

  • 봉성율
    • 공업화학
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    • 제35권2호
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    • pp.79-84
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    • 2024
  • 메탄은 풍부하고 재생 가능한 탄화수소이지만, 온실가스로서 지구 온난화를 발생시킨다. 따라서 메탄을 유용한 화학물질이나 에너지원으로의 변환이 필요하다. 메탄올은 메탄의 부분 산화 반응을 통해 합성할 수 있는 간단하고 풍부한화학물질이다. 메탄올은 화학 공급 원료나 수송 연료로 사용될 뿐만 아니라, 저온 연료 전지의 연료로도 적합하다. 그러나 메탄올의 전기화학 산화는 복잡하고 다단계의 반응이므로, 이 반응을 이해하고 최적화하기 위해서는 새로운 전기화학촉매와 반응 메커니즘의 연구가 필요하다. 본 총설에서는 메탄올 산화 반응 메커니즘 및 최근 연구 동향과 향후 연구 방향을 고찰하였다.

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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    • 제15권1호
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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.