• Applied Chemistry for Engineering
• /
• v.25 no.4
• /
• pp.346-351
• /
• 2014

With the world population's continuous growth and urban industrialization, capacitive deionization (CDI) has been proposed as a next-generation water treatment technology to augment the supply of water. As a future water treatment method, CDI attracts significant attention because it offers small energy consumption and low environmental impact in comparison to conventional methods. Carbon electrodes, which have large surface area and high conductivity, are mainly used as electrode materials of choice for the removal of ions in water. A variety of carbon materials have been investigated, including their adsorption-desorption behavior in accordance to the specific surface area and pore size distribution. In this review, we analyzed and highlighted these carbon materials and looked at the impact of pore size distribution to the overall CDI efficiency. Finally, we propose an optimal condition in the interplay between micropores and mesopores in order to provide the best electrosorption property for these carbon electrodes.

• Journal of the Korean Chemical Society
• /
• v.37 no.8
• /
• pp.702-710
• /
• 1993

Electrochemical reduction of thionyl chloride has been carried out at glassy carbon and molybdenum electrodes, the surface of which is modified by binuclear tetradentate schiff base Co(II), Ni(II),Cu(II) and Fe(II) complexes. 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 catalytic effects of SOCl$_2$ reduction were larger on glassy carbon electrodes compared to molybdenum electrodes and enhancements in reduction current of up to 120${\%}$ at the glassy carbon electrodes. The reduction currents of thionyl chloride were increased and the reduction potentials were shifted to the negative potential when scan rates became faster. The reduction of thionyl chloride was proceed to diffusion controlled reaction.

• Applied Chemistry for Engineering
• /
• v.34 no.5
• /
• pp.493-500
• /
• 2023

In this study, we developed an impedance sensor capable of controlling electrode polarization by coating iridium oxide (IrO_x) on the surface of the screen-printed carbon electrode. IrO_x was deposited on the surface of carbon electrodes according to the number of cycles (0~50 cycles) by cyclic voltammetry. Observation of scanning electron microscope images revealed that the size and number of IrO_x particles increased as the number of cycles increased. The changes in impedance responses as a function of the NaCl concentration of the as-obtained sensors were investigated using electrochemical impedance spectroscopy. The sensors manufactured in 50 cycles exhibited the best coefficient of determination and reproducibility, attributed to the well-controlled electrode polarization. We further demonstrated the usefulness of the IrO_x-based sensor as a diagnosis sensor for dry eye syndrome by comparing the results of the commercially available osmometer and our sensor using actual solution samples.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.04a
• /
• pp.91-94
• /
• 2003

탄소재료는 높은 전기전도도 및 기계적 강도, 화학적 안정성, 큰 비표면적(1000~3000 $m^2$/g) 등의 특성 때문에 연료전지, 리튬이온 이차전지, 전기이중층 캐패시터(electric double layer capacitor, EDLC)의 전극활물질로 주목받고 있다[1]. 일반적으로 활성탄소섬유는 1000~3000 $m^2$/g의 비표면적을 갖기 때문에 종래의 필름 콘덴서와 세라믹 콘덴서에 비해 비약적인 고용량(체적당 수천 배, Farad급)을 얻을 수 있다. 전기이중층 캐패시터는 수명이 반영구적이며 사용온도의 범위가 넓고 안전하다는 장점을 지니고 있으며 이러한 캐패시터의 성능은 전극으로 사용되는 활성탄소 섬유의 비표면적, 세공의 크기, 구조 및 형태, 표면의 관능기 및 전기 전도도 등의 특성에 크게 좌우된다[1-3]. (중략)

• Journal of the Korean Chemical Society
• /
• v.41 no.1
• /
• pp.1-11
• /
• 1997

Electrode surface reaction on three carbon materials(glassy carbon, synthesized graphite, graphite foil) in 0.5 M K2SO4 electrolyte is investigated by impedance spectroscopy during anodic polarization. The double layer capacitance of the graphite foil electrode is relatively higher than that of other two materials. The change of capacitance parameter C due to chemical adsorption on glassy carbon and synthesized graphite(PVDF graphite) is observed in 0.5 M K2SO4 solution at anodic polarization. In general, the faradic impedance on glassy carbon depends on anodic polarization, and the change of impedance parameter on graphite foil at anodic polarization is not remarkable, because this reaction is controlled by field transport.

• Applied Chemistry for Engineering
• /
• v.22 no.1
• /
• pp.31-36
• /
• 2011

Tetrafluoromethane ($CF_4$) has been used as the plasma etching and chemical vapor deposition (CVD) gas for semiconductor manufacturing processes. However, the gas need to be removed efficiently because of their strong absorption of infrared radiation and the long atmospheric lifetime which cause global warming effects. A waterjet gliding arc plasma system in which plasma is combined with the waterjet was developed to effectively produce OH radicals, resulting in efficient destruction of $CF_4$ gas. Design factors such as electrode shape, electrode angle, gas nozzle diameter, electrode gap, and electrode length were investigated. The highest $CF_4$ destruction of 93.4% was achieved at Arc 1 electrode shape, $20^{\circ}$ electrode angle, 3 mm gas nozzle diameter, 3 mm electrode gap and 120 mm electrode length.

• Journal of the Korean Electrochemical Society
• /
• v.3 no.3
• /
• pp.173-177
• /
• 2000

The synthetic carbon was coated with tin oxide and copper by fluidized-bed chemical vapor deposition method. $(CH_3)_4Sn\;and\;Cu(hfac)_{2s}$ were employed as the metallic organic precursor, respectively. The modified synthetic carbons were used for lithium secondary battery anode to investigate their coating effects on electrochemical characteristics as alternative anode materials for lithium secondary batteries. The electrode which prepared by the synthetic carbons(MCMB) coated with tin oxide gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. But the cyclability was improved by coating with copper on the surface of the tin oxide coated carbon, which plays an important role as an inactive matrix buffering volume changes.

• Journal of the Microelectronics and Packaging Society
• /
• v.17 no.1
• /
• pp.75-80
• /
• 2010

Electroless nickel plating on porous carbon substrate was investigated. The pore sizes of carbon substrates were 16-20 ${\mu}m$ and over 20 ${\mu}m$. The carbon surface was changed from hydrophobic to hydrophilic after immersing the substrate in an ammonia solution for 40 min at $60^{\circ}C$. The contact angle of water was decreased from $85^{\circ}$ to less than $20^{\circ}$ after ammonia pretreatment. The content of phosphorous in nickel deposit was decreased with increasing pH and then deposits became crystallized. The thickness of nickel deposit was increased with increasing pH. The minimum concentration of $PdCl_2$ for the electroless nickel plating was 5 ppm and the thickness of nickel was not significantly affected by the concentration of $PdCl_2$.

• Resources Recycling
• /
• v.30 no.6
• /
• pp.19-27
• /
• 2021

Electrically conductive mortar used in industrial carbon material byproducts was manufactured and analyzed in this study. The contents of the carbon material and mixed water were controlled, and the distance between electrodes was set to 0.42 m and 0.88 m. The carbon material was graphite with a layered structure. The carbon material was used as fine powder and aggregate substitutes according to particle size. The average particle sizes of each materials were 18.4㎛ and 546.1 ㎛ and the electrical conductivities were 62.3 S/m and 32.5 S/m, respectively. To maintain similar mortar flow in each sample, the water content was increased with increasing carbon material, and accordingly, the porosity showed an increasing trend. When electrode distance of the mortar (week 6) was 0.42 m, the voltage-current values were 342 V-1.48 A (S20) and 349 V-1.44 A (S30). For electrode distance of 0.88 m, these values were 513 V-0.98 A (S20) and 500 V-1.01 A (S30). The exothermic properties improved with increasing carbon material content and decreasing electrode distance.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.92.2-92.2
• /
• 2011

고분자전해질 연료전지 (PEMFC)의 가격 결정 요인 중 막 전극 접합체 (MEA)가 차지하는 비중은 약 45%정도이며, 이것을 구성하는 주요 부품인 기체 확산층 (GDL)은 carbon paper나 carbon cloth 형태가 사용되고 있다. 그렇지만 GDL을 제조하는 공정은 매우 복잡하고, 그 가격이 너무 높은 단점이 있다. 본 연구에서는 카본블랙, 흑연 등의 탄소화합물과 polymer binder를 이용하여 단순화된 공정으로 GDL을 제조하였다. 또한, GDL의 물리적 특성이 전극 성능에 미치는 영향을 분석하기 위하여 표면 morphology, 접촉각 및 표면에너지, 전기전도도, 기체투과도, porosity, pore distrivution 등을 측정하였고, 각각의 GDL 표면에 동량의 Pt 촉매를 도포하여 MEA를 제작한 후 그 성능을 평가하였다.