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AAO를 사용한 고분자전해질 연료전지의 공기극 촉매층 구조 제어
조윤환,조용훈,정남기,안민제,강윤식,정동영,임주완,성영은,Cho, Yoon-Hwan,Cho, Yong-Hun,Jung, Nam-Gee,Ahn, Min-Jeh,Kang, Yun-Sik,Chung, Dong-Young,Lim, Ju-Wan,Sung, Yung-Eun 한국전기화학회 2012 한국전기화학회지 Vol.15 No.2
고분자전해질 연료전지 (PEMFC)의 공기극을 양극산화 알루미늄 (AAO) 템플레이트를 이용하여 제조하고 촉매층의 구조적 특성을 주사현미경 (SEM) 측정과 BET (Brunauer-Emmett-Teller) 분석을 통해 알아보았다. SEM 측정을 통해 일정한 크기와 모양의 Pt nanowire 가 규칙적으로 형성된 것을 확인할 수 있었다. BET 분석을 통해 AAO 템플레이트로 인하여 20-100 nm 크기의 기공 분포가 증가한 것을 확인하였다. 단위전지 성능평가와 임피던스 측정을 통하여 막-전극접합체 (MEA)의 전기화학적 특성을 분석하였다. 그 결과, AAO 템플레이트를 이용하여 제조한 MEA는 촉매층의 구조 개선으로 인하여 물질 전달 저항을 감소시킬 수 있었으며, 25%의 단위전지 성능이 향상되었다. The cathode catalyst layer in polymer electrolyte membrane fuel cells (PEMFCs) was fabricated with anodic aluminum oxide (AAO) template and its structure was characterized with scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The SEM analysis showed that the catalyst layer was fabricated the Pt nanowire with uniform shape and size. The BET analysis showed that the volume of pores in range of 20-100 nm was enhanced by AAO template. The electrochemical properties with the membrane electrode assembly (MEA) were evaluated by current-voltage polarization measurements and electrochemical impedance spectroscopy. The results showed that the MEA with AAO template reduced the mass transfer resistance and improved the cell performance by approximately 25% through controlling the structure of catalyst layer.
DNN에서 효율적인 학습을 위한 활성화 함수에 대한 고찰
조윤환(Yoon-Hwan Cho),서영덕(Young-Deok Seo),박대준(Dae-Jun Park),정제창(Je-Chang Jeong) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.11
Deep learning is definitely notable in various classification field. DNN(Deep Neural Network) is a kind of algorithm for deep learning. It becomes important to choose a suitable activation function to make learn the various DNN structure. In this paper, we summarize the history of activation function playing a key role in DNN and propose an improvement direction for state of the art activation function.
MEA 제조 방법에 따른 직접 메탄올 연료전지의 성능저하 현상 평가
조윤환(Cho, Yoon-Hwan),조용훈(Cho, Yong-Hun),박현서(Park, Hyun-Seo),원호연(Won, Ho-Youn),성영은(Sung, Yung-Eun) 한국신재생에너지학회 2007 신재생에너지 Vol.3 No.1
Catalyst coated membrane [CCM] type and catalyst coated substrate [CCS] type of membrane electrode assembly [MEA] were manufactured and evaluated their performance. Degradation test were conducted to find the difference of long term stability in two types of MEA and the factor for performance degradation problem occurred. Performance degradation test of single cell in two different types of MEA were carried out when current density was 200mA/cm^{2}. The degradation test had proceeded for 230 hours and performance degradation was checked by I-V curve and impedance measurement at regular intervals. Also, MEA before/after operation and changes of catalyst layer were characterized by SEM, TEM, and XRD. Maximum power density of CCM type was higher than that of CCS type. Meanwhile, an increase of particle size of catalyst and an increase of impedance resistance after long term operation were observed. In the case of using CCM type MEA, the performance was deteriorated 38% of initial performance. In the case of using CCS type MEA, the performance was deteriorated 43% of initial performance. In consideration of difference of initial performance, performance of CCM type is higher than that of CCS type but both types had similar problems during degradation test.
고분자전해질 연료전지의 MEA 제조방법에 따른 성능비교
조용훈(Cho, Yong-Hun),조윤환(Cho, Yoon-Hwan),박인수(Park, In-Su),최백범(Choi, Baeckbom),정대식(Jung, Dae-Sik),성영은(Sung, Yung-Eun) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.06
The PEMFC behavior is quite complex and is influenced by several factors, including composition and structure of electrodes and membrane type. Fabrication of MFA is important factor for proton exchange membrane fuel cell. MFA of PEMFC with hot pressing and direct coating method were prepared, and performances were evaluated and compared each other. The effect of MEA preparation methods, hot pressing methods and direct coating methods, on the cell performance was analyzed by impedance spectroscopy and SEM. The performance of PEMFC wi th direct coat ing method was better than wi th hot pressing method because membrane internal resistance and membrane-:-interfacial resistance were reduced by elimination of hot pressing process in MEA fabrication. In addition the micro structure of MEA with direct coating method reveals uniform interface between membrane and catalyst layer.
고분자전해질 연료전지의 환원전극 백금 담지촉매의 백금 담지비에 따른 성능변화
조용훈(Cho, Yong-Hun),조윤환(Cho, Yoon-Hwan),박현서(Park, Hyun-Seo),성영은(Sung, Yung-Eun) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.06
This study focuses on a determination of amount of Pt in the Pt/C for catalysts of polymer electrolyte membrane fuel cells (PEMFC). PEMFC offer low weight and high power density and being considered for automotive and stationary power applications. The PEMFC performance is influenced by several factors, including catalysts and structure of electrode and membrane type. Catalyst of electrode is important factor for PEMFC. One of the obstacles prevent ing polymer electrolyte membrane fuel cells from commercialization is the high cost of noble metals to be used as catalyst, such as platinum To effectively use these metals, they have to be will dispersed to small particles on conductive carbon supports. The optimal amount of Pt in Pt/C for cathode catalyst was investigated by using polarization curves in single cell with H₂/O₂ operation.
고분자전해질 연료전지의 MEA 제조방법과 백금 담지촉매의 백금 담지비율에 따른 성능분석
조용훈(Cho, Yong-Hun),조윤환(Cho, Yoon-Hwan),박현서(Park, Hyun-Seo),성영은(Sung, Yung-Eun) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11
고분자전해질 연료전지의 MEA를 CCM (Catalyst Coated Membrane) CCS(Catalyst Coated Substrate) 형태로 각각 제조하고 백금담지 비율이 서로 다른 백금 담지촉매를 각각 적응하여 MEA를 CCM형태로 제조하여 단위전지 성능평가를 수행하였다 백금담지 비율이 다른 촉매를 적용한 CCM형태 MEA의 표면을 SEM (scanning electron microscopy)으로 분석하였으며, 단위전지 성능평가를 수행하는 동시에 EIS (Electrochemical Impedance Spectroscopy)를 통하여 MEA의 저항을 분석하였다. 고분자전해질 연료전지의 성능은 MEA의 제조방법과 백금담지 촉매의 백금담지비율에 따라 크게 변함을 확인 할 수 있었다.
조용훈(Cho, Yong-Hun),조윤환(Cho, Yoon-Hwan),박현서(Park, Hyun-Seo),정남기(Jung, Nam-Gee),성영은(Sung, Yung-Eun) 한국신재생에너지학회 2007 한국신재생에너지학회 학술대회논문집 Vol.2007 No.06
The MEA with the catalyst layer containing PtRu black and 60 wt. %Pt/C as their anode and cathode catalysts. For find to effect of carbon support, the MEA with platinum black for cathode catalyst was fabricated. The performance of the MEA with the catalyst layer containing (PtRu black:60 wt.% Pt/C) as their anode and cathode catalyst has shown competitively higher value than the performance of the MEA with the catalyst layer containing (PtRu black:Pt black) as their anode and cathode catalyst.
PdPt/C 촉매의 고분자전해질 연료전지의 산화극 촉매 적용
조용훈(Cho, Yong-Hun),최백범(Choi, Baeck-Beom),조윤환(Cho, Yoon-Hwan),박현서(Park, Hyun-Seo),성영은(Sung, Yung-Eun) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11
PdPt/C (Pd:Pt atomic ratio of around 19:1 60wt, %) 촉매를 고분자전해질 연료전지용 전극 촉매소재의 적용하였다. PdPt/C 촉매를 산화극 촉매로, 환원극 촉매로는 Pt/C 촉매를 사용하고 반대로 산화극 촉매는 Pt/C 촉매, 환원극 촉매로는 PdPt/C 촉매를 사용했을 때, PdPt/C 촉매를 산화극과 환원극 촉매로 동시에 사용했을 때의 고분자전해질 연료전지의 단위전지 성능을 각각 비교하였다. PdPt/C촉매를 산화극에만 적용했을 때에 Pt/C 상용촉매를 산화극과 환원극에 모두 적용했을 때의 성능만큼 좋은 성능을 확인할 수 있었다. 환원극 촉매는 Pt/C를 사용하고 산화극 촉매를 PdPt/C Pt/C Pd/C를 사용하였을 매의 성능을 비교하였다. Pd/C를 산화극 촉매로 사용한 단위전지가 나머지 두 경우의 성능에 비하여 현저히 떨어짐을 확인할 수 있었다. 이는 극소량의 Pt 량을 포함한 PdPt/C 촉매가 고분자전해질 연료전지의 산화극 Pt/C 촉매의 대체촉매로 사용 가능함을 보여준다.