• Title/Summary/Keyword: 환원전위

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Studies on the Electrochemical Properties of $TiO_{2-x}$ Thin Films Prepared by Air Oxidation and Water Vapor Oxidation (공기 산화와 수증기 산화에 의해 제조된 $TiO_{2-x}$ 박막의 전기화학적 성질에 관한 연구)

  • Yong-Kook Choi;Ki-Hyung Chjo;Q-Won Choi;Jeong-Sup Seong;Jeong-Geun Oh
    • Journal of the Korean Chemical Society
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    • v.37 no.4
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    • pp.401-407
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    • 1993
  • The titanium oxide thin films were prepared by air oxidation and water vapor oxidation. The electrochemical properties of the electrodes were studied in 1M NaOH solution. The peak potentials of oxygen reduction from cyclic voltammogram techniques were observed at aroung -0.9 ∼ -1.0 V vs. SCE and the reaction was totally irreversible process. The electrochemical properties of titanium dioxide electrodes prepared by water vapor oxidation exhibited different from the air oxidized electrodes, but it was similar to single crystal $TiO_2$. The peak potentials of oxygen reduction were observed at slightly more positive than flat band potentials and depended on pH.

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Analysis of AM and AEM Oxides Behavior in a SF Electrolytic Reduction Process (사용후핵연료 전기환원 공정에서의 알카리, 알카리토 금속 산화물들의 거동 분석)

  • 박병흥;강대승;서중석;박성원
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.268-277
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    • 2004
  • process (ACP), electrochemical properties of high heat-generating alkali and alkali earth oxides in molten salt were measured and the behavior of those elements were analyzed. The reduction potentials of Cs, Sr, and Ba in a molten LiCl-$Li_2O$ system were more cathodic than that of Li and closely located one another. Thus, it is expected that the alkali and alkali earth would not hinder the reaction mechanism which is via lithium reduction. Alkali and alkali earth metals are likely to recycle into molten salt when the process is operated beyond metal reduction potentials and the effect of electric current on the mass transport is also determined by measuring the metal concentrations in the molten salt phase at different current conditions.

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Effect of Nitrate on Iron Reduction and Phosphorus Release in Flooded Paddy Soil (논토양에서 질산 이온이 철의 환원과 인의 용출에 미치는 영향)

  • Chung, Jong-Bae
    • Korean Journal of Environmental Agriculture
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    • v.28 no.2
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    • pp.165-170
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    • 2009
  • The increase in P availability to rice under flooded soil conditions involves the reductive dissolution of iron phosphate and iron (hydr)oxide phosphate. However, since $NO_3^-$ is a more favourable electron acceptor in anaerobic soils than Fe, high$NO_3^-$ loads function as a redox buffer limiting the reduction of Fe. The effect of adding $NO_3^-$ on Fe reduction and P release in paddy soil was investigated. Pot experiment was conducted where $NO_3^-$ was added to flooded soil and changes of redox potential and $Fe_2^+$, $NO_3^-$ and $PO_4^{3-}$ concentrations in soil solution at 10 cm depth were monitored as a function of time. Redox potential decreased with time to -96 mV, but it was temporarily poised at about 330${\sim}$360 mV when $NO_3^-$ was present. Nitrate addition to soil led to reduced release of $Fe_2^+$ and prevented the solubilization of P. Phosphate in pore water began to rise soon after incubation and reached final concentrations about 0.82 mg P/L in the soil without $NO_3^-$ addition. But, in the soil with $NO_3^-$ addition, $PO_4^{3-}$ in pore water was maintained in the range of 0.2${\sim}$0.3 mg P/L. The duration of inhibition in $Fe_2^+$ release was closely related to the presence of $NO_3^-$, and the timing of $PO_4^{3-}$ release was inversely related to the $NO_3^-$ concentration in soil solution. The results suggest that preferential use of $NO_3^-$ as an electron acceptor in anaerobic soil condition can strongly limit Fe reduction and P solubilization.

A Study on the Electrochemical and Spectroscopic Property Analysis of Organic Eeletroluminescence Materials(BCP, PEDOT, TAZ, TPD) (유기전기발광물질들(BCP, PEDOT, TAZ, TPD)의 전기화학적.분광학적 특성분석)

  • Choi, Don-Soo;Bae, Jeong-Hyo;Kim, Dae-Kyeong;Lee, Jae-Duck;Kim, Mu-Young
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1564-1566
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    • 2004
  • BCP의 이온화에너지 (Ionization Potential; IP)는 5.72ev와 전자친화도 (Electron Affinity; EA)는 2.85ev이며, PEDOT의 IP=5.74ev와 EA=3.3sev이고, TAZ의 IP=6.45ev와 EA=2.77ev, TPD는 IP=5.75ev와 EA=2.S8eV를 나타내었다. 그리고 BCP와 TAZ는 산화전위의 시작점과 증가곡선의 전위 변곡점과의 차이(정공층 갭)와 환원전위의 시작점과 변곡점의 차이(전자층 갭)가 서로 비슷하였으며, PEDOT과 TPD의 경우 정공층의 갭이 전자층의 갭보다 크게 나타났다.

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A Study on environmental-friendly Cleaning for Si-wafers (환경친화적인 실리콘 웨이퍼 세정 연구)

  • Yoon, Hyoseob;Ryoo, Kunkul
    • Clean Technology
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    • v.6 no.1
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    • pp.79-84
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    • 2000
  • In this study, to reduce the consumption of chemicals in cleaning processes, Si-wafers contaiminated with metallic impurities were cleaned with electrolyzed water(EW), which was generated by the electrolysis of a diluted electrolyte solution or ultra pure water(UPW). Electrolyzed water could be controlled for obtaining wide ranges of pH and ORP(oxidation-reduction potential). The pH and oxidation-reduction potential of anode water and cathode water were measured to be 4.7 and +1000mV, and 6.3 and -550mV, respectively. To analyze the amount of metallic impurities on Si-wafer surfaces, ICP-MS was introduced. Anode water was effective for Cu removal, while cathode water was more effective for Fe removal.

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Oxidation-Reduction Titration Curve Both Half Reactions Homogeneous in Coefficient (산화-환원 적정 곡선)

  • Choi, Q-Won
    • Journal of the Korean Chemical Society
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    • v.11 no.4
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    • pp.159-164
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    • 1967
  • An exact expression of the titration fraction as a function of the potential is derived for the cases where the coefficients of the both half reactions involved in the titration are homogeneous. It shows that the potential is independent of the concentration of the reagents not only at the equivalence point but also at all titration fractions. The sharpness of the end point detection by potentiometric method is shown to depend not only on the difference of the normal potentials involved but also strongly on the number of electrons transferred in each half reaction. The inflexion point of the potentiometric titration curve is shown to be slightly off from the equivalence point, including the cases where the number of electrons involved are equal. Completeness of the reaction in the course of titration is analyzed, too, mostly in terms of equilibrium constant, thus most of the results are applicable to any type of equilibrium in a single phase with particular relationship of coefficients of chemical equation.

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Electrochemical Studies on $Sm^3+$-ARS Complexes ($Sm^3+$-ARS착물의 전기화학적 연구)

  • Son, Byoung-Chan
    • The Journal of Natural Sciences
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    • v.11 no.1
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    • pp.33-39
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    • 1999
  • Electrochemical behaviors of $Sm^3+$-ARS complexes has been investigated by d.c.polarography, differential pulse polarography and cyclic voltammetry. $Sm^3+$forms 1 : 3 adsorptive complexes with ARS.The reduction potential of complex wave $(P_2)$ shifted more negatively than the ligand wave $(P_1)$. The linear calibration curves of decreasing $P_1$ and increasing $P_2$ is obtained when $Sm^3+$ concentration varies from TEX>$2{\times}10^{-6}$ M to $3.2{\times}10^{-5}$ M.

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Sterilization and ecofriendly neutralization of seawater using electrolysis (전기분해에 의한 해수살균 및 친환경 중화에 관한 연구)

  • Yang, Jeong-Hyeon;Choi, Jong-Beom;Yun, Yong-Sup
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.3
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    • pp.276-280
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    • 2017
  • In this study, we investigated the effect of sterilization and the neutralization of treated ballast water using seawater electrolysis. The electrolysis apparatus has a cation-selective membrane for passing the cation and a titanium electrode in each cell. We examined the sterilization effect after an incubation period of 24 hr. The oxidation reaction during electrolysis caused, the solution to become strongly acidic due to the generation of a hydroxyl group, and the oxidation reduction potentials(ORP) was increased to 800 - 1200mV. After the reduction reaction, the solution became alkaline(pH 9 - 12), and ORP was decreased to - 900 - - 750 mV. It might be possible to control the pH of ballast water through electrolysis. In addition, we demonstrated the effects of sterilization of ballast water containing generated hypochlorous acid using electrolysis under high ORP condition.

콜타르 핏치로부터 제조한 리튬 이온 이차전지 부극재료의 특성

  • 홍현진;양갑승;윤광의;이동준
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.508-511
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    • 1998
  • 최근 들어 이동통근의 발달로 말미암아 이에 적합한 초경량, 초소형 전지의 개발이 요구된 Li은 지구상에 존재하는 흔한금속이며 그 환원 전위가 3.04V고 금속 중 가장 큰 전위값을 갖고 있다. 현재 상업화되어 있는 리튬이차전지는 정극에 대부분 LiCoO$_2$을 부극에 탄소재료를 사용하고 있다. (중략)

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