• Title/Summary/Keyword: Electrochemical pretreatment

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Effect of Different Pretreatments on Indium-Tin Oxide Electrodes

  • Choi, Moonjeong;Jo, Kyungmin;Yang, Haesik
    • Bulletin of the Korean Chemical Society
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    • v.34 no.2
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    • pp.421-425
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    • 2013
  • The effect of pretreatment on indium-tin oxide (ITO) electrodes has been rarely studied, although that on metal and carbon electrodes has been enormously done. The electrochemical and surface properties of ITO electrodes are investigated after 6 different pretreatments. The electrochemical behaviors for oxygen reduction, $Ru(NH_3){_6}^{3+}$ reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are compared, and the surface roughness, hydrophilicity, and surface chemical composition are also compared. Oxygen reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are highly affected by the type of the pretreatment, whereas $Ru(NH_3){_6}^{3+}$ reduction is almost independent of it. Interestingly, oxygen reduction is significantly suppressed by the treatment in an HCl solution. The changes in surface roughness and composition are not high after each pretreatment, but the change in contact angle is substantial in some pretreatments.

Evaluation of Pretreatment Effect and Non-enzymatic Glucose Sensing Performance of Carbon Fibers Tow Electrode (탄소섬유 토우의 전처리 효과와 비효소적 포도당 센싱 성능 평가)

  • Min-Jung Song
    • Korean Chemical Engineering Research
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    • v.62 no.1
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    • pp.13-18
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    • 2024
  • To develop flexible electrode materials for wearable devices, we investigated the electrochemical characteristics of carbon fibers tow according to pretreatment. And an electrochemical non-enzymatic sensor was fabricated using glucose as a target. The carbon fibers tow was pretreated through desizing and activation processes, and activation was performed in two ways: chemical oxidation and electrochemical oxidation. Surface morphology of carbon fibers tow samples was observed by SEM and their electrochemical characteristics and sensing performance were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Carbon fibers tow samples showed improved electrochemical properties such as reduced Ret, ΔEp, and increased Ip through pretreatment. And similar electrochemical properties were obtained with both activation methods. We selected electrochemically activated carbon fibers tow as the final electrode material for application of electrochemical sensor. The non-enzymatic glucose sensor based on this electrode has an enhanced sensitivity of 0.744 A/mM (in a linear range of 0.09899~3.75423 mM) and 0.330 mA/mM (3.75423~50 mM), respectively. Through this study, the possibility of using carbon fibers tow was confirmed as an electrode material. It is expected to be used as basic research for development of high-performance flexible electrode materials.

Simultaneous Electroanalysis of Nitric Oxide and Nitrite

  • Oritani, Tadato;Okajima, Takeyoshi;Kitamura, Fusao;Ohsaka, Takeo
    • Journal of the Korean Electrochemical Society
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    • v.5 no.4
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    • pp.209-211
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    • 2002
  • The simultaneous sensing of nitric oxide (NO) and its metabolite, nitrite $(NO_2^-)$ has been studied by Osteryoung square-wave voltarnmetery (OSWV) in physiological pH solution (0.1 M phosphate buffer solution, pH 7.2). Using an electrochemically pretreated glassy carbon (GC) electrode, OSWV was successfully applied to observe the well-separated oxidation peaks at ca. 0.58 and 0.80V vs. Ag/AgCI for NO and $(NO_2^-)$, respectively. This clear separation between the NO and $(NO_2^-)$ oxidation peaks may be due to the formation of surface oxides (e.g., quinone (C=O) or carboxylic $(COO^-)$ group) and surface defects introduced by the electrochemical pretreatment of GC electrodes.

ASSESSMENT OF ACTIVITY-BASED PYROPROCESS COSTS FOR AN ENGINEERING-SCALE FACILITY IN KOREA

  • KIM, SUNGKI;KO, WONIL;BANG, SUNGSIG
    • Nuclear Engineering and Technology
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    • v.47 no.7
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    • pp.849-858
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    • 2015
  • This study set the pyroprocess facility at an engineering scale as a cost object, and presented the cost consumed during the unit processes of the pyroprocess. For the cost calculation, the activity based costing (ABC) method was used instead of the engineering cost estimation method, which calculates the cost based on the conceptual design of the pyroprocess facility. The calculation results demonstrate that the pyroprocess facility's unit process cost is $194/kgHM for pretreatment, $298/kgHM for electrochemical reduction, $226/kgHM for electrorefining, and $299/kgHM for electrowinning. An analysis demonstrated that the share of each unit process cost among the total pyroprocess cost is as follows: 19% for pretreatment, 29% for electrochemical reduction, 22% for electrorefining, and 30% for electrowinning. The total unit cost of the pyroprocess was calculated at $1,017/kgHM. In the end, electrochemical reduction and the electrowinning process took up most of the cost, and the individual costs for these two processes was found to be similar. This is because significant raw material cost is required for the electrochemical reduction process, which uses platinum as an anode electrode. In addition, significant raw material costs are required, such as for $Li_3PO_4$, which is used a lot during the salt purification process.

Effect of Surface Pretreatment on Film Properties Deposited by Electro-/Electroless Deposition in Cu Interconnection (반도체 구리 배선공정에서 표면 전처리가 이후 구리 전해/무전해 전착 박막에 미치는 영향)

  • Lim, Taeho;Kim, Jae Jeong
    • Journal of the Korean Electrochemical Society
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    • v.20 no.1
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    • pp.1-6
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    • 2017
  • This study investigated the effect of surface pretreatment, which removes native Cu oxides on Cu seed layer, on subsequent Cu electro-/electroless deposition in Cu interconnection. The native Cu oxides were removed by using citric acid-based solution frequently used in Cu chemical mechanical polishing process and the selective Cu oxide removal was successfully achieved by controlling the solution composition. The characterization of electro-/electrolessly deposited Cu films after the oxide removal was then performed in terms of film resistivity, surface roughness, etc. It was observed that the lowest film resistivity and surface roughness were obtained from the substrate whose native Cu oxides were selectively removed.

Effect of Ultrasound During Pretreatment on the Electrochemical Etching of Aluminum and Its Capacitance (초음파를 이용한 전처리가 알루미늄의 전기화학적 에칭 및 정전용량에 미치는 효과)

  • Jung, Insoo;Tak, Yongsug;Park, Kangyong;Kim, Hyungi;Kim, Sungsoo
    • Corrosion Science and Technology
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    • v.10 no.1
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    • pp.37-42
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    • 2011
  • Aluminum was electrochemically etched in acid solution and the surface area was magnified by the formation of etch pits. Etched aluminum was covered with a compact and dense dielectric oxide film by anodization and applied to the aluminum electrolytic capacitor electrode. Capacitance of aluminum electrolytic capacitor is closely related with surface area, which depends on size and number of etch pits. Size of etch pits need to be controlled because inside of the pits can be buried by the formation of dielectric oxide film. In this work, the effect of ultrasound pretreatment on the aluminum etch pit formation and capacitance were investigated. Additionally, the relationship between the second etching effect on pit size and capacitance was studied.

Effect of Pretreatments on Graphene Coated Bipolar Plate of PEMFC on Electrochemical (전처리가 그래핀을 코팅한 고체고분자 연료전지 분리판의 전기화학적 특성에 미치는 영향)

  • Cha, Seong-Yun;Lee, Jae-Bong
    • Corrosion Science and Technology
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    • v.13 no.6
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    • pp.224-232
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    • 2014
  • Effect of pretreatments on the graphene coated bipolar plate of proton exchange membrane fuel cell(PEMFC) was investigated in simulated environments for PEMFC by using electrochemical measurement techniques. Interfacial contact resistance(ICR) between the graphene coated bipolar plate and the gas diffusion layer(GDL) was measured. The value of ICR decreased with an increase in compaction stress($20N/cm^2{\sim}220N/cm^2$). ICR of graphene coated bipolar plate was higher than that of bare 316L stainless steel. However, Potentiodynamic measurement results showed that the corrosion resistance of graphene coated bipolar plate was higher than that of bare 316L stainless steel. $H_2SO_4$ acid pretreatment was the most effective among various pretreatments. The lowest ICR and the corrosion current density were obtained when using $H_2SO_4$ solution pretreatment.