• Clean Technology
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• v.18 no.2
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• pp.183-190
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• 2012

Electrochemical regeneration of the iron chloride waste solution from PCB etching reduces environmental contamination and produces copper as by-product, so the economic feasibility is high. But iron chloride waste solution contains iron and copper and the reactions occurring in the electrolytic cell are complicated. In this work, the oxidation of iron chloride and copper deposition were examined through batch electrolysis and the optimum conditions of the process parameters were found. The oxidation of ferrous chloride was achieved easily to the desired level. The copper deposition efficiency was high in the reaction using the carbon cathode when the copper density was 12 g/L with the electric current density of $350mA/cm^2$, and the ratio of the $Fe^{2+}$ ion was high. In addition, the possibility of the scale-up was confirmed in continuous operation of bench reactor using the optimum conditions obtained.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.463-466
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• 2006

직접 알콜 연료전지는 액체인 알콜을 직접 연료전지에 공급하여 연소시킴으로써 높은 효율을 갖는 휴대용전원으로 주목받는 장치이다. 직접 알콜 연료전지에 담지체로 사용되는 탄소 소재는 넓은 표면적과 우수한 전기전도도를 가지고 있다는 장점 있으나 금속 촉매와의 상호작용이 약하여 촉매 활성에 영향을 주지 못한다. 산화물을 담지체로 사용할 경우 이러한 금속-담지체 간의 상호작용으로 인한 촉매활성 증가 및 입자성장 억제의 효과를 기대할 수 있다. 본 연구에서는, 안티몬 도핑된 주석산화물 (Sb-doped SnO2 : ATO nanoparticle)을 직접 메탄올 연료전지용 담지체어 적용하였으며 합성 과정은 다음과 같다. SnC14 5H2O SbC13, NaOH, HCl 수용액 혼합물을 삼구 플라스크에 넣고 $100^{\circ}C$ 온도에서 환류(reflux) 시킨 후 세척 및 건조하여 Air 분위기에서 열처리하였다. 합성된 산화물 수용액에 폴리올 방법으로 합성된 백금 콜로이드를 담지하였으며, 세척과 건조를 통하여 산화물에 담지된 백금 촉매를 촉매를 합성하였다. 촉매의 구조분석을 위해 XRD, TEM을 사용하였으며, 전극촉매로서의 활성을 평가하기 위해 cyclic voltammetry을 평가하였다. 본 연구에서는 백금의 담지량에 따른 Costripping voltammetry특성과 메탄올 및 에탄올 산화 반응 특성에 대하여, 탄소를 담지체로 사용한 Pt/C 촉매와 비교 평가하였다. 알콜 산화반응 평가결과, 주석산화물에 담지한 촉매가 탄소를 담지체로 사용한 촉매보다 우수한 활성을 나타내었으며 활성증가는 메탄올에 비해 에탄올 산화 반응의 경우 크게 증가하였다. 막과 비교해 보았다. $ZrO_2$ 입자는 전도성이며 동시에 친수성을 나타내기 때문에 상용 막에 비하여 함수율 및 수소이온 전도도가 우수하게 나타났다. 복합막의 이러한 물성은 $100^{\circ}C$이상의 고온에서 전해질 막 내의 물 관리를 용이하게 한다. 단위 전지 운전 온도 $130^{\circ}C$, 상대습도 37%의 운전 조건에서도 상당히 우수한 전지 성능을 보임에 따라 고온/저가습 조건에서 상용 Nafion 112 막보다 우수한 막 특성을 나타냄을 확인하였다.소/배후방사능비는 각각 $2.18{\pm}0.03,\;2.56{\pm}0.11,\;3.08{\pm}0.18,\;3.77{\pm}0.17,\;4.70{\pm}0.45$ 그리고 $5.59{\pm}0.40$이었고, $^{67}Ga$-citrate의 경우 2시간, 24시간, 48시간에 $3.06{\pm}0.84,\;4.12{\pm}0.54\;4.55{\pm}0.74 $이었다. 결론 : Transferrin에 $^{99m}Tc$을 이용한 방사성표지가 성공적으로 이루어졌고, $^{99m}Tc$-transferrin의 표지효율은 8시간까지 95% 이상의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{99m}Tc$<

• Journal of Energy Engineering
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• v.23 no.3
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• pp.157-162
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• 2014

In this research, we investigate electrical performance and electrochemical properties of carbon supported Pt (Pt/C) that is synthesized by polyol method. With the Polyol_Pt/C that is adopted for oxygen reduction reaction (ORR) as cathode of proton exchange membrane fuel cells (PEMFCs), their catalytic activity and ORR performance and electrical performance are estimated and compared with commercial Pt/C(Johnson Mattey) catalyst. Their electrochemically active surface (EAS) area are measured by cyclic voltammetry (CV), respectively. On the other hand, regarding ORR activity and electrical performance of the catalysts, (i) linear sweeping voltammetry by rotating disk electrode and (ii) PEMFC single cell tests are used. The CV measurement demonstrate EAS of Polyol_Pt/C is compared with commercial JM_Pt/C. In case of Polyol_Pt/C, its half-wave potential, kinetic current density are excellent. Based on data obtained by half-cell test, when PEMFC single cell tests are carried out, current density measured at 0.6V and maximum power density of the PEMFC single cell employing Polyol_Pt/C are better than those employing commercial Pt/C. Conclusively, Polyol_Pt/C synthesized by modified polyol process shows better ORR catalytic activity and PEMFC performance than other catalysts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.88-88
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• 2007

Chemical mechanical polishing (CMP) 공정은 그 어원에서 알 수 있듯이 슬러리의 화학적인 요소와 웨이퍼에 가해지는 기계적 압력에 의해 결정되는 평탄화 기술이다. 최근, 금속배선공정에서 높은 전도율과 재료의 값이 싸다는 이유로 Cu률 사용하였으나, 디바이스의 구조적 특성을 유지하기 위해 높은 압력으로 인한 새로운 다공성 막(low-k)의 파괴와, 디싱과 에로젼 현상으로 인한 문제점이 발생하게 되었다. 이러한 문제점을 해결하고자, 본 논문에서는 Cu 표면에 Passivation layer를 형성 및 제거하는 개념으로 공정시 연마제를 사용하지 않으며, 낮은 압력조건에서 공정을 수행하기 위해, 전해질의 농도 변화에 따른 선형추의전압전류법과 순환전압전류법을 사용하여 전압활성화에 의한 전기화학적 반응이 어떤 영향을 미치는지 연구하였다.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.730-734
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• 1993

The electrochemical reduction behavior or Biliverdin (BV) in N,N-dimethylformamide solvent was studied by DC polarography, cyclic voltammetry and the controlled potential coulometry. The reduced product was indentified by UV-Vis spectroscopy. In DC polarogram, two reduction waves of BV were founded. The half wave potentials of two reduction waves were -0.71 and -0.91 V vs. Ag/Ag$^+$ respectively. The current type of the 1st reduction wave was diffusion-controlled and the 2nd was diffusion current containing a little kinetic current. The 1st electrochemical reduction process was irreversible and BV reduced to Bilirubin.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.337-343
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• 2013

Membrane reactors have been showing a promising future and attracted increasing attention in the scientific community as they possess advantages in terms of enhanced catalytic activity and selectivity, combination of processes (reaction and separation), simplicity in process design, and safety in operation. In particular, solid electrolyte membrane reactor principles are realized in fuel cells, electrolyzers and reactors for hydrogenation of carbon dioxide and other economically viable reactions. In this review, as a young generation of ion conducting materials, high temperature proton conductors are discussed in terms of the current status of material development and their various applications.

• Journal of the Korean Chemical Society
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• v.66 no.6
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• pp.436-441
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• 2022

Because the nanoporous electrodes has large electrochemical surface areas, extensive studies have been focused on their fabrication methods. In this paper, a method for introducing a nanoporous gold (NPG) structure on the surface of an ultramicroelectrode (UME) using potentiostatic anodization was investigated. A well-defined NPG structure was introduced on the surface of the UME when a potential of 1.3 V was applied in 0.1 M phosphate buffer solution (pH 8) containing 1 M KCl. The anodic oxidation efficiency was investigated by observing the effect of the applied potential, the reaction time, and the size of the electrode on the roughness factor (R_f) of the prepared NPG-UMEs. In a short time of about 10 minutes, NPG-UME with a large R_f value of about 2000 could be prepared, which could be effectively used for electrochemical glucose detection. The results shown in this work are expected to have great applicability when performing electrochemical analysis with a small sample volume.

• Prospectives of Industrial Chemistry
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• v.23 no.2
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• pp.12-22
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• 2020

전기변색 물질은 전압을 인가하였을 때 산화-환원 반응을 통해 흡수도나 투과도 같은 광학적 물성 변화를 보인다. 이러한 전기변색 물질에 기반한 전기변색 소자는 높은 투과도 변화, 낮은 구동 전압, 간단한 소자 구조 등 다양한 장점을 가지고 있어 차세대 투명 디스플레이로 각광받고 있다. 최근에는 이러한 전기변색 소자에 변색 특성 이외에 유연성 및 에너지 저장성 등 다양한 기능을 추가하는 연구가 활발하게 이루어지고 있다. 본 기고문에서는 전기변색 소자의 기본적인 구동 원리 및 다기능 개발 동향 등에 대해 알아보고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.1033-1041
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• 2012

Performance evaluation of a direct carbon fuel cell (DCFC) was conducted according to coals and a graphite particle. Several fuel properties such as thermal reactivity, textural structure, gas adsorption characteristic, and functional groups on the surface of fuels were investigated and their effects on electrochemistry were discussed. The strong carbon structure inside of fuels led the rapid potential decreasing in high current density region, because it caused small surface area and low pore volume. The functional groups on the surface were related to the low current density region. The maximum current density and power density of fuels were affected by the total carbon content in fuels. The effect of operating conditions such as stirring rate and operating temperature was investigated in this study.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.2
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• pp.97-104
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• 2012

A porous $TiO_2$ pellet was electrochemically converted to the metallic titanium by using a $CaCl_2$ molten salt system at $850^{\circ}C$. Ni-$TiO_2$ and graphite electrodes were used as cathode and anode, respectively. The electrochemical behaviour of $TiO_2$ pellet was determined by a constant voltage control electrolysis. Various reaction intermediates such as $CaTiO_3$, $Ti_2O$ and $Ti_6O$ were observed by XRD analysis during electrolysis of the pellet. Once $TiO_2$ pellet was converted to a porous metallic structure, the porous structure disappeared by sintering and shrinking with increasing the reaction time at high temperature.