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Feasibility of dual catalyst electrode for self-humidifying proton exchange fuel cells(PEMFCs)
고영돈,김화중 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
TiO<sub>2</sub> and ZrO<sub>2</sub> are well known metal oxides that have been extensively used in a variety of applications. Among such a variety of applications, hollow-structured hydrophilic TiO<sub>2</sub> nanoparticles (HTiO<sub>2</sub>) with high specific surface areas are used as a part of dual catalyst electrode in self-humidifying PEMFC. Pt-metal oxide layer are placed between Pt/C layer and membrane. Pt-metal oxide, specifically Pt-HTiO<sub>2</sub> functions for the generation of water molecules by Pt sites and its retention by hydrophilic HTiO<sub>2</sub>. The generation of water molecules on Pt sites becomes possible through the consumption of H<sub>2</sub> and O<sub>2</sub> crossing the membrane, finally making the operation of PEMFC under zerohumidity. In this study, well-defined Pt-hollowed structured TiO<sub>2</sub> (Pt-HTiO<sub>2</sub>) was synthesized and its physical properties were confirmed by various analytical tools such as XRD, BET, SEM and TEM. The cell performance was evaluated under various relative humidity (i.e. RH 100 %, 60 %, 40 % and 0 %).
고영돈,서재원,김화중 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1
The hollow structured TiO<sub>2</sub> (HTiO<sub>2</sub>) has a high specific surface area as compared with normal TiO<sub>2</sub> spheres because it is composed of an empty space and a small pore structure. The HTiO<sub>2</sub> was synthesized using the different sizes of SiO<sub>2</sub> as a template and Pt nanoparticles were successfully deposited on HTiO<sub>2</sub>. X-ray diffraction (XRD) analysis confirmed the crystalline phase of HTiO<sub>2</sub>, and the specific surface area and pore size distribution was evaluated by Brunauer-Emmet-Teller method (BET) measurement. Water management is an important factor in PEMFC. The Pt-HTiO<sub>2</sub> electrode was applied to increase the backdiffusion ability of the water generated from the cathode to the anode, thereby preventing the anode from drying. Moreover, Pt-HTiO<sub>2</sub> plays a role in the generation of water through the chemical reaction using oxygen and hydrogen crossing the membrane. The MEA was fabricated by applying as a dual electrode and tested under various relative humidity.
Process Effect on the RMS Roughness of HfO2 Thin Films Grown by MOMBE
고영돈,Pyung Moon,윤일구,Moon-Ho Ham,명재민 한국전기전자재료학회 2007 Transactions on Electrical and Electronic Material Vol.8 No.2
In this paper, the process effect on the RMS roughness of the HfO2 thin films grown by metal organic molecular beam epitaxy was investigated. The measured RMS roughness is examined to characterize the surface morphology. In order to analyze the factor effects, the significant factors of both the main and the interaction effects were extracted through the effect analysis. In order to compare the regression model with the variable transformation, the effect of each factor and the model efficiency are calculated. The methodology can allow us to analyze the effects between the process parameters related to the process variability.
TSV 웨이퍼 공정용 Si<sub>3</sub>N<sub>4</sub> 후막 스트레스에 대한 공정특성 분석
강동현,구중모,고영돈,홍상진,Kang, Dong Hyun,Gu, Jung Mo,Ko, Young-Don,Hong, Sang Jeen 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.3
With the recent advent of through silicon via (TSV) technology, wafer level-TSV interconnection become feasible in high volume manufacturing. To increase the manufacturing productivity, it is required to develop equipment for backside passivation layer deposition for TSV wafer bonding process with high deposition rate and low film stress. In this research, we investigated the relationship between process parameters and the induced wafer stress of PECVD silicon nitride film on 300 mm wafers employing statistical and artificial intelligence modeling. We found that the film stress increases with increased RF power, but the pressure has inversely proportional to the stress. It is also observed that no significant stress change is observed when the gas flow rate is low.
이웅희,양희나,고영돈,김익태,김화중 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
Recently, polymer electrolyte membrane fuel cell (PEMFC) has received a huge amount of attention as one of alternative energy sources where Pt is most widely used as electrochemical catalyst However, Pt is so expensive that it contributes more than 50 % of total cost for PEMFC. This is one of main reason preventing it from the commercialization. In order to resolve this problem, Pt -transition metal (Pt-M, M = Pd, Fe and Ni) alloy catalysts are synthesized and deposited on nitrogen doped carbon black (NCB). Electrochemical and physical properties of Pt-M alloys/nitrogen-doped carbon black (Pt-M/NCB), especially the oxygen reduction reaction (ORR) are investigated by various instruments. Finally, a single cell test is conducted for Pt-M/NCB as the cathode catalyst.
최범석,양희나,고영돈,김익태,김화중 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0
Hydrophilic ZrO2 nanoparticles are prepared by sol-gel process to which Pt nanoparticles are deposited. During sol-gel process, acetic acid and ammonia are added to control the particle size and well-defined ZrO2 nanoparticles are finally obtained through the calcination at 600ºC for 4 h under air flow. Platinum nanoparticles is deposited on the zirconia by Pt salt reduction and characterized. ZrO2 and Pt-ZrO2 nanoparticles are identified by XRD, SEM, EDS and XRF analyses. Dual catalyst layers comprising Pt/C and Pt-ZrO2 are prepared and adopted to the membrane electrolyte assembly for self-humidifying PEMFC. Elecrochemical and physical properties are analyzed and the cell performance is evaluated and discussed.
In-situ 졸-겔 법을 이용한 저가습 작동용 수소 이온 교환막 연료전지용(PEMFC) 나피온/TiO<sub>2</sub> 복합막
최범석 ( Beomseok Choi ),고영돈 ( Youngdon Ko ),김화중 ( Whajung Kim ) 한국공업화학회 2019 공업화학 Vol.30 No.1
저가습 작동을 위한 수소 이온 교환막 연료전지용 Nafion/TiO<sub>2</sub> 복합막을 졸-겔 법을 이용하여 제조하였다. 이때 Nafion 막에 TiO<sub>2</sub> 나노 입자를 함침시키기 위하여 TiO<sub>2</sub> 전구체 용액에 1일부터 7일까지 함침 시간을 달리하여 복합막을 제조 하였다. 담금 시간이 증가할수록 Nafion막 내에 함침되는 TiO<sub>2</sub> 함량이 증가하였다. TiO<sub>2</sub> 함량이 증가함에 따라 막의 표면의 친수성이 증가하면서 접촉각은 감소하는 것을 보여주었다. 물 흡수력(water uptake)과 복합막을 통한 수소 이온 전도도는 담금 시간이 4일인 경우 가장 높게 나타났고 4일 이상인 경우에는 오히려 감소하는 경향을 보여주었다. 담금 시간이 7일인 경우에는 큰 TiO<sub>2</sub> 입자들이 막의 표면과 내부에 생성되어 애노드에서 캐소드로의 수소 이온 전도를 방해하게 되는 결과를 초래하였다. 전지 성능 시험 결과 물 흡수력 및 수소 이온 전도도의 결과와 상당히 일치하는 것을 보여주었다. 즉, 0.6 V에서 담금 시간이 1일, 3일, 4일 및 7일인 경우 전류 밀도가 상대 습도(relative humidity, RH) 40%에서 각각 0.54, 0.6, 0.63 A/㎠ 및 0.49 A/㎠를 나타내었다. Nafion 분산액과 TiO<sub>2</sub> 입자를 혼합하여 제작한 막과 Nafion 115를 이용하여 RH 40%에서 수행한 전지 성능 결과와 비교할 때 졸-겔 법을 이용하여 제조한 복합막의 경우 약 66%의 전지 성능 향상을 얻을 수 있었다. Nafion/TiO<sub>2</sub> composite membranes were prepared via an in-situ sol-gel process with different immersing periods from 1 day to 7 days for the low humidifying proton exchange membrane fuel cell. As the immersing time increased, the TiO<sub>2</sub> content within the Nafion membrane increased. The contact angle decreased with the increased TiO<sub>2</sub> content in the composite membrane due to the increased hydrophilicity. The water uptake and proton conductivity reached to the highest level for 4 day immersing period, then decreased as the immersing period increased. A 7 days of immersing time was shown to be too long because too much TiO<sub>2</sub> aggregates were formed on the membrane surface as well as interior of the membrane, interfering the proton transfer from anode to cathode. Cell performance results were in good agreement with those of the water uptake and proton conductivity; current densities under a relative humidity (RH) of 40% were 0.54, 0.6, 0.63 A/㎠ and 0.49 A/㎠ for the immersing time of 1, 3, 4 and 7 days, respectively at a 0.6 V. The composite membrane prepared via the in-situ sol-gel process exhibited the enhancement in the cell performance under of RH 40% by a maximum of about 66% compared to those of using the recasting composite membrane and Nafion 115.