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폴리피롤 막으로 변성시킨 유리질 탄소 및 백금 전극에서 Cr(Ⅵ) 이온의 정량
유광식,우상범,정지영,Yoo, Kwang Sik,Woo, Sang Beom,Jyoung, Jy Young 대한화학회 1999 대한화학회지 Vol.43 No.4
본 연구에서는 유리질 탄소전극과 백금 전극의 표면에 폴리피롤 막을 도포 시킨 PPy/GC 및 PPy/Pt 변성전극을 제조하고, 이들 변성 전극들을 작업전극으로 구성한 3-전극 장치를 이용하여 Cr(VI)의 정량분석을 시도하였다. 변성전극들은 +1.0V∼-1.0V를 50 mV/sec로 전위를 걸어주어 순환 전압 전류법으로 쉽게 제조할 수 있었으며, 26회 반복 주사함으로써 연구에 필요한 막의 두께를 조절하였다. PPy/GC 변성전극에서 Cr(VI)의 환원 반응은 +0.6V∼-0.5V(vs. Ag/AgCl)까지 넓은 범위에서 환원되는 경향을 보였으며,-0.25V(vs.Ag/AgCl)의 전위에서 최대 환원 봉우리를 가짐을 알 수 있었다. 이 전위에서 검량곡선을 조사한 결과, 0.1 ppm에서 60.0 ppm의 농도범위에서 기울기가 1.75 mA/ppm이고, 상관계수가 0.998인 좋은 직선관계를 가졌다. PPy/Pt 변성전극에서도 Cr(VI)의 환원 거동은 PPy/GC 변성전극과 유사하였으며, 검량곡선은 1.0 ppm∼60.0ppm의 농도범위에서 직선관계를 가졌다. 이때의 기울기와 상관계수는 각각 0.5 mA/ppm 및 0.923이었다. 그러나 선택성은 PPy/GC 변성전극이 약 3 배정도 우수하였다. PPy/GC 변성전극에서 Cu(II), As(III), pb(II) 및 Cd(II)등은 환원 경향을 보이지 않았으므로, Cr(VI)의 정량분석에는 방해하지 않았다. Studies have been carried out on the fabrication of PPy/GC and PPy/Pt electrode modified with polypyrrole film and determination of Cr(VI) by using 3-electrode system with modified electrodes. Modified electrodes were able to easily fabricated by cyclic voltammetry scanned from +1.0V to -1.0V(vs. Ag/AgCl) at 50 mV/sec. Film thickness could be controlled at same condition by the number of cycling up to 26 times. Reduction behaviour of Cr(VI) at PPy/GC electrode could be seen at wide potential ranges from +0.6V to -0.5V(vs. Ag/AgCl), and maximum reduction peak potential of the ion was observed at -0.25V(vs.Ag/AgCl). Calibration graph at its potential was linear from 0.1 ppm to 80.O ppm. Slope factor and relative coefficient were 1.75 mA/ppm and 0.998, respectively. Reduction behaviour of Cr(VI) at PPy/Pt electrode was similar to PPy/GC electrode, Calibration graph was linear from l.0 ppm to 60.0 ppm. Slope factor and relative coefficient were 0.5mA/ppm and 0.923, respectively. But PPy/GC modified electrode had about 3 times higher sensitivity than PPy/Pt modified electrode. Reduction behaviour of Cu(II), As(IlI), Pb(II), and Cd(II) couldn't be seen at PPy/GC electrode,Its metals had not lnterfered with Cr (VI) determination.
조준현(Cho, Junhyun),박재만(Park, Jaeman),오환영(Oh, Hwanyeong),민경덕(Min, Kyoungdoug),정지영(Jyoung, Jy-Young),이은숙(Lee, Eunsook) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11
The gas diffusion layer (GDL) consists of two main parts, the GDL backing layer, called as a substrate and the micro porous layer (MPL) coated on the GDBL. In this process, carbon particles of MPL penetrates to the GDBL consequently forms MPL penetration part. In this study, the micro porous layer (MPL) penetration thickness is determined as a design parameter of the GDL which affect pore size distribution profile through the GDL inducing different mass transfer characteristics. The pore size distribution and water permeability characteristics of the GDL are investigated and the cell performance is evaluated under fully/low humidification conditions. Transient response and voltage instability are also studied. In addition, to determine the effects of MPL penetration on the degradation, the carbon corrosion stress test is conducted. The GDL that have deep MPL penetration thickness shows better performance in high current density region because of enhanced water management, however, loss of penetrated MPL parts is shown after aging and it induces worse water management characteristics.
기체확산층의 마이크로다공층 구조 설계에 따른 고분자전해질형 연료전지의 성능 및 내구성에 관한 실험적 연구
오환영(Hwanyeong Oh),조준현(Junhyun Cho),박재만(Jaeman Park),민경덕(Kyoungdoug Min),정지영(Jy-Young Jyoung),이은숙(Eunsook Lee) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
The Gas Diffusion Layer(GDL) is a main component of a Polymer Electrolyte Membrane Fuel Cell(PEMFC) as a passage of not only hydrogen and air, used as fuels, but also water for humidifying membrane. Ion conductivity of Nafion<SUP>®</SUP> used as a membrane of PEMFC is proportional to amount of water in membrane. However, excessive water causes water flooding, which decreases the performance of a PEMFC by blocking pores in the GDL. Therefore, for enhanced performance of a PEMFC, it is important to concern how to design the micro porous layer (MPL) of the GDL, which is a key component for water management. Moreover, its durability has to be also considered for the commercialization of a PEMFC. In this study, as design parameters of MPL, a less hydrophobic MPL is inserted between the normal MPL and the substrate of the GDL, and the additional pore path is formed inside the MPL. Finally, the effects of these structural changes in the MPL on performance and durability are investigated.