• Title/Summary/Keyword: Electro-Oxidation

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Preparation of Porous Carbon Fiber by Using MgO Powder and Its Characteristics of Catalysts for Fuel Cell (MgO를 이용한 다공성 탄소 섬유 제조 및 이를 이용한 연료전지용 촉매 특성)

  • Nam, Kidon;Kim, Sang-Kyung;Lim, Seongyop;Peck, Donghyun;Lee, Byoungrok;Jung, Doohwan
    • Korean Chemical Engineering Research
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    • v.46 no.6
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    • pp.1142-1147
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    • 2008
  • Nano-structured porous carbon fiber(PCF) for the catalyst supports of the direct methanol fuel cell (DMFC) were prepared from the mesophase pitch by using the nano-MgO powders. Specific surface area of the PCFs was $8{\sim}58m^2/g$ and surface pore structures had almost meso pore diameter of 10~20 nm which were depending on the amount of MgO spheres. Aqueous reduction method was used to load 60 wt% PtRu on the prepared PCF supports. The electro-oxidation activity and single cell performance of the 60 wt% Pt-Ru catalysts were measured by cyclic voltammetry and unit cell test. The performances of these catalysts increased by 5~10% compared with one of commercial catalyst.

Morphology Control of NiO Catalysts on NiCrAl Alloy Foam Using a Hydrothermal Method (수열합성법을 이용한 NiCrAl 합금 폼 위에 합성된 NiO 촉매 형상 제어)

  • Sin, Dong-Yo;Lee, Eun-Hwan;Park, Man-Ho;Ahn, Hyo-Jin
    • Korean Journal of Materials Research
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    • v.26 no.7
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    • pp.393-399
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    • 2016
  • Flower-like nickel oxide (NiO) catalysts were coated on NiCrAl alloy foam using a hydrothermal method. The structural, morphological, and chemical bonding properties of the NiO catalysts coated on the NiCrAl alloy foam were investigated by field-emission scanning electron microscopy, scanning electron microscopy-energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, respectively. To obtain flower-like morphology of NiO catalysts on the NiCrAl alloy foam, we prepared three different levels of pH of the hydrothermal solution: pH-7.0, pH-10.0, and pH-11.5. The NiO morphology of the pH-7.0 and pH-10.0 samples exhibited a large size plate owing to the slow reaction of the hydroxide ($OH^-$) and nickel ions ($Ni^+$) in lower pH than pH-11.5. Flower-like NiO catalysts (${\sim}4.7{\mu}m-6.6{\mu}m$) were formed owing to the fast reaction of $OH^-$ and $Ni^{2+}$ by increased $OH^-$ concentration at high pH. Thus, the flower-like morphology of NiO catalysts on NiCrAl alloy foam depends strongly on the pH of the hydrothermal solution.

Thickness Control of Electroplating Layer for Copper Pillar Tin Bump (구리기둥범프 용 전해도금 층 제어)

  • Moon, Dae-Ho;Hong, Sang-Jeen;Park, Jong-Dae;Hwang, Jae-Ryong;Soh, Dea-Wha
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2011.10a
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    • pp.903-906
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    • 2011
  • The electroplating and electro-less plating methods have been applied for the high density chip interconnect of the Copper Pillar Tin Bump (CPTB) preparation. The CPTB was prepared, which had been electroplated about $100{\mu}m$ pitch of copper layer firstly, and then the Tin layer was deposited on the copper pillar surface to protect the oxidation of it. It was also very important to get uniform thickness of electroplated copper layer, though it was difficult and sensitive. In order to control the thickness distribution, it was examined that the current separating disk of Insulating Gate with a hole in the center was installed between electrodes. The current flows through the center hole of the Insulating Gate in the cylindrical electroplating bath and the other parts were blocked to protect current flowing. The main current flowed through the center hole of the Insulating Gate directly to the opposite electrode of wafer disk. As the results, it was verified that the copper layer was thick in the center part of wafer disk with distribution of thinner to the outer part toward edge.

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Characteristics of Sr2Ni1.8Mo0.2O6-δ Anode for Utilization in Methane Fuel Conditions in Solid Oxide Fuel Cells

  • Kim, Jun Ho;Yun, Jeong Woo
    • Journal of Electrochemical Science and Technology
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    • v.10 no.3
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    • pp.335-343
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    • 2019
  • In this study, $Sr_2Ni_{1.8}Mo_{0.2}O_{6-{\delta}}$ (SNM) with a double perovskite structure was investigated as an alternative anode for use in the $CH_4$ fuel in solid oxide fuel cells. SNM demonstrates a double perovskite phase over $600^{\circ}C$ and marginal crystallization at higher temperatures. The Ni nanoparticles were exsolved from the SNM anode during the fabrication process. As the SNM anode demonstrates poor electrochemical and electro-catalytic properties in the $H_2$ and $CH_4$ fuels, it was modified by applying a samarium-doped ceria (SDC) coating on its surface to improve the cell performance. As a result of this SDC modification, the cell performance improved from $39.4mW/cm^2$ to $117.7mW/cm^2$ in $H_2$ and from $15.9mW/cm^2$ to $66.6mW/cm^2$ in $CH_4$ at $850^{\circ}C$. The mixed ionic and electronic conductive property of the SDC provided electrochemical oxidation sites that are beyond the triple boundary phase sites in the SNM anode. In addition, the carbon deposition on the SDC thin layer was minimized due to the SDC's excellent oxygen ion conductivity.

Selective tyrosine conjugation with a newly synthesized PCB -TE2A-luminol bifunctional chelator

  • Subramani Rajkumar;Hyun Park;Abhinav Bhise;Seong Hwan Cho;Jung Young Kim;Kyo Chul Lee;Jeongsoo Yoo
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.7 no.2
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    • pp.85-91
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    • 2021
  • Selective amino acid conjugation of bulky antibodies is a valuable asset for real-time diagnosis and therapy. However, selective conjugation incorporating a chelate-bearing radioactive atom into an antibody without affecting its immunoreactivity is a challenging task. A bifunctional chelator (BFC), a selective amino acid-targeting probe, and a linker have been developed to overcome this problem. Here, we report the synthesis of a novel propylene cross-bridged chelator (PCB)-1,8-N,N'-bis-(carboxymethyl)-1,4,8,11-tetraazacyclotetradecane (TE2A)-luminol BFC via a click reaction and radiolabel it with a 64Cu ion for tyrosine-selective conjugation of trastuzumab. In the initial optimization study, we tried different oxidative addition conditions such as electro-oxidation, hemin, horseradish peroxidase, iodogen tube, chloramine-T, and iodo beads. In this study, up to 82% of 64Cu-PCB-TE2A-luminol was conjugated with the antibody in an iodo bead-catalyzed oxidative addition reaction with an isolated yield of 24.4%.

Preparation of Uniform Porous Carbon from Mesophase Pitch and Its Characteristics of Catalyst Support for the Direct Methanol Fuel Cell (메조페이스 핏치로부터 균질한 다공성 탄소 제조 및 이를 이용한 직접 메탄올 연료전지의 촉매 담지체 특성)

  • Nam, Ki-Don;Kim, Tae-Jin;Kim, Sang-Kyung;Lee, Byoung-Rok;Peck, Dong-Hyun;Ryu, Seung-Kon;Jung, Doo-Hwan
    • Applied Chemistry for Engineering
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    • v.17 no.2
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    • pp.223-228
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    • 2006
  • Pore-size controlled porous carbons for the catalyst supports of the direct methanol fuel cell were prepared from the mesophase pitch by using the silica spheres with different sizes. Pitch solution in THF and spheres were mixed, carbonized and etched by 5 M NaOH to make porous carbon. Specific surface area of the porous carbons was $14.7{\sim}87.7m^2/g$ and average pore diameter was 50~550 nm which were dependent on the size of silica spheres. Aqueous reduction method was used to load 60 wt% PtRu on the prepared porous carbon supports. The electro-oxidation activity of the supported 60 wt% Pt-Ru catalysts was measured by cyclic voltammetry and unit cell test. For the 60 wt% Pt-Ru/porous carbon synthesized by 50 nm silica, current density value in the cyclic voltammetry test was $123mA/cm^2$ at 0.4 V and peak power density in the unit cell test were 105 and $162mW/cm^2$ under oxygen at 60 and $80^{\circ}C$, respectively.

Occurrence and Influence of acid Leachate by Pyrite in Underground Rocks of Road Construction Field in the Miryang Area (밀양지역 도로건설 현장 지반암석내 분포하는 황철석에 의한 산성침출수 발생과 영향)

  • Chae, Sun Hee;Jeong, Chan Ho;Lee, Yu Jin;Lee, Yong Cheon;Shin, Sang Sik;Park, Jun Sik;Ou, Song Min
    • The Journal of Engineering Geology
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    • v.28 no.3
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    • pp.501-512
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    • 2018
  • The acid leachate derived from the sulfide mineral such as pyrite can cause problems such as aging of infrastructure and environment contamination around the civil construction site. The purpose of this study is to assess the environmental effect of an acid leachate derived from pyrite in the Miryang area under road construction. In this study, 13 samples of situ core were used for the net acid generation (NAG) experiment. The chemical composition including pH, oxidation and reduction potential (ORP) and electrical conductance of water samples produced from the NAG test was analyzed. In additional, five polished thin sections of rock cores were made for electro microprobe analyses. In the results of the NAG tests, 7 samples showed lower values than pH 3.5. It strongly indicated that these areas are under the environmental and infrastructure damage by the acid leachate. The chemical type of the 7 samples was classified as the $Fe(Ca)-SO_4$ type, which is totally a different type compared to general groundwater. The concentration of total sulfur ranges from 0.004% to 12.5%. 6 rock samples are plotted on a potentially acid forming zone in the relation diagram between the total sulfide and NAG-pH. In conclusion, it is suggested that a protection method against an environmental demage and an infrastructure corrosions by the acid leachate should be prepared in all of areas under a road construction.