• 반도체디스플레이기술학회지
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• 제7권4호
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• pp.45-49
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• 2008

For the commercialization of polymer electrolyte membrane fuel cell (PEMFC), some serious problems such as the decrease of platinum use as catalysts and a larger overpotential of oxygen reduction reaction (ORR) at cathode must be solved. In this study, 20%Pt/C and 20%PtCo/C catalysts for the cathode of PEMFC were synthesized from the chemical reduction method and evaluated using an electrochemical measurement. The ORR activity of synthesized 20%Pt/C and 20%PtCo/C had higher than that of the 20%Pt/C on the market. The synthesized 20%PtCo/C with the cobalt concentration (Pt:Co atomic ratio) from 5 to 20% showed the highest ORR activity.

• 한국세라믹학회지
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• 제37권3호
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• pp.227-232
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• 2000

The LSM-YSZ composite electrode as a mixture of LSM and YSZ shows percolation characteristics. It was identified that the polarization resistance of LSM-YSZ composite electrode depend on YSZ connectivity by changing powder size ratio of the DLSM/DYSZ. That is, YSZ in composite electrode showed low electrochemical activity without YSZ connectivity. However, the polarization resistance decreased abruptly with YSZ connectivity due to high electrochemical activity of YSZ in composite electrode. Because the amount of three phase boundary is dependent on LSM and YSZ particle size, the polarization resistance of cathode decreases as LSM and YSZ particle size decreases.

• Journal of Ceramic Processing Research
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• 제19권6호
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• pp.499-503
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• 2018

In this paper, cobalt embedded in nitrogen and sulfur co-doped carbon nanotubes (CoNSTs) were synthesized for oxygen reduction reaction (ORR) catalysts. The CoNSTs were prepared through a facile heat treatment method without any templates. Different amounts of the metal salt were employed to examine the physicochemical and electrochemical properties of the CoNSTs. The CoNSTs showed the bamboo-like tube morphology with the encased Co nanoparticles in the tubes. Through the x-ray photoelectron spectroscopy analysis, the catalysts exhibited different chemical states of the nitrogen and sulfur species. As a result, the CoNST performed high activity toward the ORR in an acidic condition with the onset potential of 0.863 V (vs. reversible hydrogen electrode). It was clearly demonstrated from the electrochemical characterizations that the quality of the nitrogen and sulfur species significantly influences the ORR activity rather than the total amount of the dopants.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2005년도 수소연료전지공동심포지움 2005논문집
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• pp.67-70
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• 2005

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2002년도 연료전지심포지움 2002논문집
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• pp.203-206
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• 2002

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2001년도 연료전지심포지움 2001논문집
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• pp.167-170
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• 2001

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2004년도 수소연료전지공동심포지움 2004논문집
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• pp.185-190
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• 2004

• Journal of Electrochemical Science and Technology
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• 제2권3호
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• pp.131-135
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• 2011

It is, in general, believed that during the activation process, the proton conductivity increases due to wetting effect and the electrochemical resistance reduction, resulting in an increase in the fuel cell performance with time. However, until now, very scant information is available on the understanding of activation processes. In this study, dominant variables that effect on the performance increase of membrane electrode assemblies (MEAs) during the activation process were investigated. Wetting, pore restructuring and active metal utilization were analyzed systematically. Unexpectedly, the changes for both ohmic and reaction resistance characterized by the electrochemical impedance spectroscopy (EIS) after initial wetting process were much smaller when considering the degree of cell performance increases. However, the EIS spectra represents that the pore opening of electrode turns into gas transportable structure more easily. The increase in the performance with activation cycles was also investigated in a view of active metals. Though the particle size was grown, the number of effective active sites might be exposed more. The impurity removal and catalytic activity enhancement measured by cyclic voltammetry (CV) could be a strong evident. The results and analysis revealed that, not merely wetting of membrane but also restructuring of electrodeand catalytic activity increase are important factors for the fast and efficient activation of the polymer electrolyte fuel cells.

• Korean Chemical Engineering Research
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• 제57권5호
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• pp.606-610
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• 2019

본 연구에서 우리는 보론 도핑된 다이아몬드 나노물질을 이용하여 유연성 탄소 섬유 기반의 전극(CF-BDD 전극)을 개발하고, 이를 비효소적 글루코스 센서에 적용하여 전기화학적 특성을 확인하였다. 이 전극은 탄소 섬유 표면에 정전하 자기조립법을 이용하여 BDD 층을 증착하여 제작하였다. 이 전극 물질의 표면 구조는 주사전자 현미경(SEM)을 이용하여 분석하였으며, 전기화학적 특성 및 센싱 성능 분석은 시간대전류법(CA)와 순환전압 전류법(CV), 전기화학 임피던스(EIS)으로 실행하였다. 제작된 CF-BDD 전극은 산화-환원 화학종과 전극 계면 간의 effective direct electron transfer와 large effective surface area, high catalytic activity의 우수한 특성들을 보였다. 결과적으로, CF 센서와 비교에서 CF-BDD 센서는 더 넓은 선형 농도 범위(3.75~50 mM)와 더 빠른 감응 시간(3초 이내), 더 높은 감도(388.8 nA/mM) 등의 향상된 센싱 특성을 보였다. 따라서, 본 연구에서 개발된 전극 물질은 다양한 전기화학 센서 뿐 아니라, 웨어러블 센서 소재로도 활용 가능할 것으로 기대된다.

• 공업화학
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• 제22권5호
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• pp.545-550
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• 2011

바이오 분자의 고정 링커로 전기전도도가 높은 방향족 공액구조의 4-(2-(4-(acetylthio)phenyl)ethynyl)benzoic acid (APBA) 분자를 합성한 후, APBA 자기조립 단분자막을 제작하였다. 제작한 APBA 자기조립 단분자막의 구조를 분석하였고, 페로센으로 고정화시킨 APBA의 자기조립 단분자막의 전기화학적 특성을 조사하였다. 부탄티올 단분자막에 APBA를 삽입시켜 혼합 단분자막을 제조하여 XPS로 금 기판에 대한 혼합 단분자막의 수직 배향성을 조사하였다. 또한, APBA 혼합 시간에 따른 APBA와 부탄티올(BT) 혼합 단분자막에 페로센을 고정화하여 전기화학적 산화 환원 특성을 조사하였다. 혼합 단분자막의 전기화학적 활성은 혼합 시간의 증가에 따라 증가하였고, 부탄티올 단분자막 기판을 APBA 용액에 36 h 침지시켰을 때 가장 높은 페로센 분자의 산화 환원 전류값을 얻었다.