• Journal of the Korean Chemical Society
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• v.38 no.12
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• pp.885-890
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• 1994

Kinetics of electrochemical polymerization of aniline on a tungsten electrode in acidic aqueous solution was studied by means of cyclic voltammetry and kinetic measurements of anodic oxidation. Aniline molecule appeared to be intially oxidized via two-electron transfer to produce oxidized deprotonated aniline ion, which subsequently undergoes nucleophilic attack to the parent aniline and results in head to tail coupling to yield a dimerized species. But, being contrary to the case of Pt electrode, the propagation of polymerization occured through attack of the monomer by the oxidized aniline monomer to polymer. The growth rate of polyaniline was slow in comparison with the growth on Pt electrode. The degradation products were confirmed to be not p-benzoquinone(BQ) but p-phenylenediamine(p-PDA) by spectrophotometry, which agrees with the fact that oxidation of p-PDA was not observed below 1.0 V.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.383-385
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• 2009

비백금계 코발트 전이금속 촉매를 탄소지지체에 담지한 뒤, 암모니아 분위기에서 $500^{\circ}C$에서 3시간 동안 열처리하는 과정을 통해 코발트 질화물 촉매를 제조했다. 제조된 촉매들의 구조와 형태를 각각 XRD, HE-TEM등을 통해 분석하였고, 전위 측정기를 이용한 CV, LSV 결과로부터 촉매의 전기화학적 산소 환원특성을 분석하여, 기존의 연료전지 양극 촉매로 사용되는 고가의 백금촉매를 대체하기 위한 비백금계로서의 가능성을 확인하였다.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.190-196
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• 2007

This study examined the nitrate removal efficiency which uses an electrowinning, and also analyzed the nitrate removal efficiency under a variety of operating conditions such as nitrate concentrations, pH, current densities, electrodes, reducing agents in order to determine optimal conditions. In addition, the multi-step electro-chemical process test has been also analyzed. During the electrowinning, the identical Zn-Zn and Pt-Ti electrodes in the insoluble oxidation electrode(Pt) has shown the highest nitrate removal efficiency in the 100 mg $NO_3^{-}$ -N/L concentration. In the concentration of 150 mg $NO_3^{-}$ -N/L, the efficiency of the Zn-Zn electrode were 70~85%, and that of Pt-Ti electrode were 40~50% without any change of pH. In the high concentration of 500 and 1,000 mg $NO_3^{-}$ -N/L, the higher the concentration, the more decrease of its nitrate removal efficiency decreased. However, the energy consumed for nitrogen removal increased when the nitrate concentration was high. As a result of the multi-step electro-chemical process test, We chose the Test 4. Because the first, most of the zinc consumed from 1 step was recovered from over the 2 step. The second, amount of consumption anode decreased with insoluble anode Pt from over the 2 step. And the third, Zn cathode increased the possibility of reusing Zn deposited. In view of the results so far achieved, the multi-step electro-chemical process would be applied to treat nitrogen involved in metal finishing wastewater.

• Resources Recycling
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• v.28 no.2
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• pp.46-53
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• 2019

In this study, the extraction and reduction behavior of platinum group metals in a non-aqueous solvent based on ionic liquids was investigated in order to confirm a new extraction technology of platinum group metals. Platinum was selectively extracted using an ionic liquid $[C_4mim]PF_6$ from a mixed solution of $PdCl_2$, $PtCl_4$ and $RhCl_3$ dissolved with concentration ratio of 10:1:0.5 M. After stripping of the metals by 1 M $HNO_3$ solution, the platinum was preferentially reduced by aqueous electrolysis on gold electrode at -0.8 V (vs. Pt-QRE). The residual palladium and rhodium were transferred to ionic liquid of $[C_4mim]Cl$. The metallic palladium and rhodium could be sequentially reduced on gold and STS304 as working electrodes by non-aqueous electrolysis, respectively.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.89-93
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• 1998

To increase performance of electrodes used in PAFC the new fabrication method was introduced and its characteristics were investigated. In the case of traditional method, electrodes show low performance because of dead catalysts. So new process was investigated to increase the utilization of Pt catalyst. After preparing PTFE/C slurry and Pt/C powder respectively, they were mixed at the ratio of 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 and electrodes were fabricated. In this case of [PTFE/C(6/4):Pt/C(1/9)=5:5], the performance of electrode, $310mA/cm^2$ at 0.7V, was most excellent.

• Resources Recycling
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• v.20 no.2
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• pp.67-73
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• 2011

In this study, for recovery of renewable noble metal from used stack of fuel cell, synthesis of platinum nano particle is established through effect of platinum solution concentration, pH value, reducing agent and dispersing agent at a volume ratio of 1 mM $H_2PtCl_6$:10 mM $NaBH_4$:8 mM Cl4TABr = 1:0.4:0.4(vol.%), pH4, $50^{\circ}C$, 160 rpm and 10min. Less than 5 nm platinum particles were synthesized using Pt leaching solution from used MEA of stack under same condition of method using simulated Pt solution. The characteristics of synthesized nano particles was illustrated by XPS analysis as the reduction of platinum ions into platinum metals(zero-valent).

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.308-308
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• 1999

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.114.1-114.1
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• 2017

불용성 전극이 고속 전기도금 공정에 사용되기 위해서는 전기화학 반응이 우수하고, 높은 내구성을 가져야 한다. 불용성 전극의 내구성은 기지층 표면전처리, 금속산화물 조성, 코팅층 두께, 소결 온도 등 다양한 전극제조 공정인자들에 의해 영향을 받는다. 본 연구에서는 불용성 전극의 내구성을 향상시키기 위해 전극 전처리 및 백금족 산화물 조성비의 공정변수로 전극을 제조하였고, 가속수명평가법을 사용하여 전극의 내구성을 평가하였다. 고속 전기도금 공정환경에서는 이리듐(Ir)계 및 탄탈륨(Ta)계 산화물 조성을 가지는 불용성전극의 내구수명이 우수한 경향을 나타내었으며, 귀금속 산화물 코팅층 두께가 얇을수록 불용성전극의 내구수명은 크게 저하되었다. 또한, Ir-Ta 조성 불용성전극의 경우 내구성 향상 기지체 표면전처리를 통해 전극의 내구수명이 10배 이상 향상되었음을 확인하였다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.99-104
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• 2003

본 연구에서는 고분자 전해질 연료전지의 촉매 슬러리 함침 도구와 전극 촉매층 형성 방법이 전극 성능에 미치는 영향을 조사하였다. 촉매 슬러리 함침 도구는 브러쉬, 스프레이 건, 스크린 프린터를 이용하였으며, 전극 촉매층 형성 방법은 스크린 프린터를 이용하여 고분자 전해질 막 위에 전극 촉매층을 형성하는 방법, 카본 페이퍼 위에 전극 촉매층을 형성하는 방법과 위의 두 방법을 결합하여 전극 촉매층을 형성하는 방법으로 구분하였다. 스크린 프린터로 제조된 전극은 브러쉬와 스프레이 건으로 제조된 전극들과 비교하여 백금 함침량을 50% 이상 줄일 수 있었으며, 고분자 전해질 막 위에 전극 촉매층을 형성하는 방법과 카본 페이퍼에 전극 촉매층을 형성하는 방법을 결합한 전극이 $1A/\textrm{cm}^2$에서 0.6V로 가장 좋은 I-V 특성을 나타내었다.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.68-72
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• 2013

Until a recent day, degradation of PEMFC MEA (membrane and electrode assembly) has been studied, separated with membrane degradation and electrode degradation, respectively. But membrane and electrode were degraded coincidentally at real PEMFC operation condition. During simultaneous degradation, there was interaction between membrane degradation and electrode degradation. The effect of electrode degradation on membrane degradation was studied in this work. We compared membrane degradation after electrode degradation and membrane degradation without electrode degradation. I-V performance, hydrogen crossover current, fluoride emission rate (FER), impedance and TEM were measured after and before degradation of MEA. Electrode degradation reduced active area of Pt catalyst, and then radical/$H_2O_2$ evolution rate decreased on Pt. Decrease of radical/$H_2O_2$ reduced the velocity of membrane degradation.