• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.216-221
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• 2012

Electrochemical reduction of carbon dioxide has been widely studied by many scientists and researchers. Recently, the production of formic acid, which is expensive but highly useful liquid material, is receiving a great attention. However, difficulties in the electrochemical reduction process and analyzing methods impede the researches. Therefore, it is important to design an adequate system, develop the reduction process and establish the analyzing methods for carbon dioxide reduction to formic acid. In this study, the production of formic acid through electrochemical reduction of carbon dioxide was performed and concentration of the product has been analyzed. Large scale batch cell with proton exchange membrane was used in the experiment. The electrochemical experiment has been performed using a series of metal catalysts. Linear sweep voltammetry (LSV) and chronoamperometry were performed for carbon dioxide reduction and electrochemical analysis using silver chloride and platinum electrode as a reference electrode and counter electrode, respectively. The concentration of formic acid generated from the reduction was monitored using high performance liquid chromatography (HPLC). The results validate the appropriateness and effectiveness of the designed system and analyzing tool.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.194-200
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• 2006

Titanium oxide films were deposited by the nozzle type HCP RT-MOCVD for the application of metal-oxide films. In the case of TTNB, after depositing films, films must be annealed at a proper temperature, but in the case of titanium ethoxide, titanium oxide films could be directly deposited by titanium ethoxide without general annealing. We could confirm that ratio of O to Ti in the films was about 2 : 1 at RF-power of 240 watt, distance between cathode and substrate of 3 cm, deposition time of 20 min, and ratio of Ar to $O_2$ of 1 : 1. Therefore, we could obtain the titanium oxide film deposited by the nozzle type HCP RT-MOCVD without an annealing process and could apply in the metal-oxide deposition process at a low temperature.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.335-342
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• 2006

Metal aluminum, of which has a low standard reduction potential, participates in the electrochemical oxidation reaction and results in the structural change and accompanying property variation of aluminum and its oxide film. Aluminum was electrochemically etched in acid solution and the surface area was magnified by the formation of high density etch pits. Etched aluminum was covered with a compact and dense dielectric oxide film by anodization and applied to the capacitor electrode. Anodization of aluminum in acid solution at low temperature makes a nanoporous aluminum oxide layer which can be used for the fabrication template of nanostructural materials. Electrochemical characteristics of aluminum turn the metal aluminum into functional materials and it will bring the diverse applications of metal aluminum.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.416-423
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• 1996

Electrochemical reduction of thionyl chloride in 1.5 M $LiAlCl_4/SOCl_2$ electrolyte solution containing tetradentate Schiff base Co(II), Ni(II), Cu(II), and Mn(II) complexes has been investigated at the glassy carbon electrode. The catalyst molecules of transition metal(II) complexes were adsorbed on the electrode surface and reduced thionyl chloride resulting in a generation of oxidized catalyst molecules. There was an optimum concentration for each catalyst compound. The current density of $SOCl_2$ reduction was enhanced up to 150% at the catalyst contained electrolyte solution. The reduction currents of thionyl chloride were increased and the reduction potentials were shifted to the negative potential as scan rates became faster. The reduction of thionyl chloride was proceeded to diffusion controlled reaction.

• Journal of IKEEE
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• v.25 no.1
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• pp.95-100
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• 2021

If we know the location of the hull block and the welding feeder in the shipyard, we can easily obtain the location information of the worker. That data is very useful for implementing a workplace safety monitoring system. However, it is difficult to apply a fixed communication network to the workplace due to the specificity of the hull structure and welding process. In this study, inductive power line communication, which can replace dedicated communication line, was reviewed. A ferrite core was used as an inductive coupler to be installed on the power cable of the welding machine, and a nano-crystalline core was applied as a coupler to be fastened to the support rod of the metal block. In order to visualize the operating principle of the proposed couplers, 3D modeling and finite element analysis were performed with the COMSOL AC/DC module. In the communication performance test using an aluminum profile, when the communication channel was formed by the contact of the welding electrode, the bandwidth was kept above 6 Mbps.

• Journal of the Korean Chemical Society
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• v.22 no.6
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• pp.365-369
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• 1978

Ellipsometric and reflectance measurements were made on an iron surface in a cathodically reduced state and in an anodically passivated state. From the differences in the optical parameters (${\Delta},\;{\psi}$, and reflectance) between the reduced (film-free) and passivated (film-covered) states the thickness and optical constants of the surface film were determined. In the passive state at -400 mV vs. SCE in borate-boric acid buffer solution the anodic film had a thickness of about 11${\AA}$ and optical constants of ${\tilde{n}}$= 2.8 - 0.8 i. This value indicates a substantial electronic conductivity of the anodic film.

• Journal of the Korean Electrochemical Society
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• v.14 no.4
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• pp.239-244
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• 2011

In this study, $Fe_3O_4$/graphene and CuO/graphene composites were synthesized by the polyol reduction method using ethylene glycol, and their performances as the anodes of lithium ion batteries were evaluated. The physical characteristics of the synthesized composites were analyzed by SEM, XRD, and TGA. In addition, their electrochemical properties were examined by the electrochemical analysis techniques such as charge/discharge performance, cyclic voltammetry, and AC impedance spectroscopy. The cells composed of $Fe_3O_4$/graphene and CuO/graphene composites showed better performance than the graphene electrode, due to the dispersion of nanosized $Fe_3O_4$ or CuO on the surface of graphene and the formation of good electrical network in the electrode. Their composites kept the reversible capacity more than 600 mAh/g even after the charging/discharging of 30 cycles.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.3
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• pp.73-76
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• 2020

Silver nanowires (AgNWs) intrinsically possess high conductivity, ductility, and network structure percolated in a low density, which have led to many advanced applications of transparent and flexible electronics. Most of these applications require patterning of AgNWs, for which photolithographic and printing-based techniques have been widely used. However, several drawbacks such as high cost and complexity of the process disturb its practical application with patterning AgNWs. Herein, we propose a novel method for the patterning of AgNWs by employing UV-curable adhesive tape with a structure of liner/adhesive layer/polyolefin (PO) film and UV irradiation to simplify the process. First, the UV-curable adhesive tape was attached to AgNWs/polyurethane (PU), and then selectively exposed to UV irradiation by using a photomask. Subsequently, the UV-curable adhesive tape was peeled off and consequently AgNWs were patterned on PU substrate. This facile method is expected to be applicable to the fabrication of a variety of low-cost, shape-deformable transparent and wearable devices.

• Journal of the Korean Electrochemical Society
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• v.18 no.3
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• pp.130-135
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• 2015

The rate capability and low-temperature characteristics of graphite electrode are investigated after surface treatment with copper phthalocyanine (CuPc) or phthalocyanine (Pc). Uniform coating layers comprising amorphous carbon or copper are generated after the treatment. The rate performance of graphite electrodes is enhanced by the surface treatment, which is more prominent with CuPc. The resistance of the graphite electrode estimated from electrochemical impedance spectroscopy and pulse resistance measurement is the smallest for the CuPc-treated graphite. It is likely that the amorphous carbon layer formed by the decomposition of Pc facilitates $Li^+$ diffusion and the metallic copper derived from CuPc improves the electrical conductivity of the graphite electrode.

• Journal of the Korean Electrochemical Society
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• v.22 no.3
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• pp.128-137
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• 2019

A lithium is the lightest metal on the earth. It has some attractive characteristics as a negative electrode material such as a low reduction potential (-3.04 V vs. SHE) and a high theoretical capacity ($3,860mAh\;g^{-1}$). Therefore, it has been studied as a next generation anode material for high energy lithium batteries. The thin lithium electrode is required to maximize the efficiency and energy density of the battery, but the physical roll-press method has a limitation in manufacturing thin lithium. In this study, thin lithium electrode was fabricated by electrodeposition under various conditions such as compositions of electrolytes and the current density. Deposited lithium showed strong relationship between process condition and its characteristics. The concentration of electrolyte affects to the shape of deposited lithium particle. As the concentration increases, the shape of particle changes from a sharp edged long one to a rounded lump. The former shape is favorable for suppressing dendrite formation and the elec-trode shows good stripping efficiency of 92.68% (3M LiFSI in DME, $0.4mA\;cm^{-2}$). The shape of deposited particle also affected by the applied current density. When the amount of current applied gets larger the shape changes to the sharp edged long one like the case of the low concentration electrolyte. The combination of salts and solvents, 1.5M LiFSI + 1.5M LiTFSI in DME : DOL [1 : 1 vol%] (Du-Co), was applied to the electrolyte for the lithium deposition. The lithium electrode obtained from this electrolyte composition shows the best stripping efficiency (97.26%) and the stable reversibility. This is presumed to be due to the stability of the surface film induced by the Li-F component and the DOL effect of providing film flexibility.