• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.160-160
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• 2010

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.463-466
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• 2006

직접 알콜 연료전지는 액체인 알콜을 직접 연료전지에 공급하여 연소시킴으로써 높은 효율을 갖는 휴대용전원으로 주목받는 장치이다. 직접 알콜 연료전지에 담지체로 사용되는 탄소 소재는 넓은 표면적과 우수한 전기전도도를 가지고 있다는 장점 있으나 금속 촉매와의 상호작용이 약하여 촉매 활성에 영향을 주지 못한다. 산화물을 담지체로 사용할 경우 이러한 금속-담지체 간의 상호작용으로 인한 촉매활성 증가 및 입자성장 억제의 효과를 기대할 수 있다. 본 연구에서는, 안티몬 도핑된 주석산화물 (Sb-doped SnO2 : ATO nanoparticle)을 직접 메탄올 연료전지용 담지체어 적용하였으며 합성 과정은 다음과 같다. SnC14 5H2O SbC13, NaOH, HCl 수용액 혼합물을 삼구 플라스크에 넣고 $100^{\circ}C$ 온도에서 환류(reflux) 시킨 후 세척 및 건조하여 Air 분위기에서 열처리하였다. 합성된 산화물 수용액에 폴리올 방법으로 합성된 백금 콜로이드를 담지하였으며, 세척과 건조를 통하여 산화물에 담지된 백금 촉매를 촉매를 합성하였다. 촉매의 구조분석을 위해 XRD, TEM을 사용하였으며, 전극촉매로서의 활성을 평가하기 위해 cyclic voltammetry을 평가하였다. 본 연구에서는 백금의 담지량에 따른 Costripping voltammetry특성과 메탄올 및 에탄올 산화 반응 특성에 대하여, 탄소를 담지체로 사용한 Pt/C 촉매와 비교 평가하였다. 알콜 산화반응 평가결과, 주석산화물에 담지한 촉매가 탄소를 담지체로 사용한 촉매보다 우수한 활성을 나타내었으며 활성증가는 메탄올에 비해 에탄올 산화 반응의 경우 크게 증가하였다. 막과 비교해 보았다. $ZrO_2$ 입자는 전도성이며 동시에 친수성을 나타내기 때문에 상용 막에 비하여 함수율 및 수소이온 전도도가 우수하게 나타났다. 복합막의 이러한 물성은 $100^{\circ}C$이상의 고온에서 전해질 막 내의 물 관리를 용이하게 한다. 단위 전지 운전 온도 $130^{\circ}C$, 상대습도 37%의 운전 조건에서도 상당히 우수한 전지 성능을 보임에 따라 고온/저가습 조건에서 상용 Nafion 112 막보다 우수한 막 특성을 나타냄을 확인하였다.소/배후방사능비는 각각 $2.18{\pm}0.03,\;2.56{\pm}0.11,\;3.08{\pm}0.18,\;3.77{\pm}0.17,\;4.70{\pm}0.45$ 그리고 $5.59{\pm}0.40$이었고, $^{67}Ga$-citrate의 경우 2시간, 24시간, 48시간에 $3.06{\pm}0.84,\;4.12{\pm}0.54\;4.55{\pm}0.74 $이었다. 결론 : Transferrin에 $^{99m}Tc$을 이용한 방사성표지가 성공적으로 이루어졌고, $^{99m}Tc$-transferrin의 표지효율은 8시간까지 95% 이상의 안정된 방사성표지효율을 보였다. $^{99m}Tc$-transferrin을 이용한 감염영상을 성공적으로 얻을 수 있었으며, $^{67}Ga$-citrate 영상과 비교하여 더 빠른 시간 안에 우수한 영상을 얻을 수 있었다. 그러므로 $^{99m}Tc$<

• Journal of Hydrogen and New Energy
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• v.25 no.4
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• pp.419-424
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• 2014

Direct ethanol fuel cell has been fabricated with ceramic membrane. A porous silicon carbide (SiC) membrane having approximately 30% porosity has been applied for a direct ethanol proton exchange membrane (DE-PEM) fuel cell. A horizontal type cell having Pt ($18mg/cm^2$) catalyst layer on both side of the ceramic membrane was used for the demonstration test. The ethanol oxidation based-fuel cell stack showed very high voltage (1.289V) and measurable current level (68mA) even though at room temperature.

• Journal of Hydrogen and New Energy
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• v.19 no.5
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• pp.423-429
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• 2008

This work was carried out to improve the performance of anodic electrocatalysts in direct ethanol fuel cell(DEFC). PtRu and $Pt_5Ru_4M$(M= Ni, Sn, Mo and W) electrocatalysts were prepared by using a $NaBH_4$ reduction method. Alloy crystal structure and particle size of electrocatalysts were characterized by X-ray diffraction(XRD) and transmission electron microscopy(TEM). The XRD analysis of the electrocatalysts revealed that the face-centered cubic(fcc) peaks shifted to slightly higher diffraction angles when third metals were added. Average size of the uniform particles was observed to be approximately $3{\sim}3.5\;nm$ from the TEM image. The electrochemical measurements were carried out in the solution 1M $H_2SO_4$ and 1M $C_2H_5OH$ at room temperature. Cyclic-voltammogram results showed that $Pt_5Ru_4W$ electrocatalyst exhibited much higher current density for ethanol oxidation of $2.73\;mA/cm^2$ than PtRu electrocatalyst of $0.73\;mA/cm^2$.

• Journal of the Korean Electrochemical Society
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• v.4 no.2
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• pp.65-69
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• 2001

The potential change, and the crossover of alcohol in a liquid-feed solid polymer electrolyte fuel cell operating at atmosphere and room temperature was investigated. Alcohol crossover was generated from all the alcohol by using the fuel. The single-cell property of direct methanol fuel cell was higher than that of other alcohol species as $31mW/cm^2$ at 0.23 V at 4.5M of methanol.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.191-194
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• 2009

PtRu based and PtSn based ternary catalysts were prepared by a conventional impregnation method using NaBH4 as reducing agent. The alloy formation, crystalline size and chemical composition of the in-house catalysts were determined by XRD, TEM and EDX, respectively. The chemical compositions of in-house catalysts were quite similar to the nominal value and good alloy formations were also observed. Further, crystalline sizes of ternary catalysts were comparatively smaller than binary catalysts and were approximately 3.5 ~ 5.5 nm. The electrochemical measurements were carried out in the solution 1 M $H_2SO_4$ with 1 M $C_2H_5OH$ at room temperature. LSV results obtained that ternary catalysts were higher current densities and specific activities. Especially, in case of tungsten addition system, Pt5Sn4W/C have the highest specific activities values and was approximately 21.2 and 3.1 times higher than that of PtRu/C and PtSn/C electrocatalyst.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.109-114
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• 2008

Though ethanol can theoretically generate 12 electrons during oxidation to carbon dioxide, the complete oxidation of ethanol is hard to achieve due to the strong bond between the two carbons in its molecular structure. Therefore, development of high activity catalyst for ethanol oxidation is necessary for the commercialization of direct ethanol fuel cell. In this study, some binary and ternary electrocatalysts of PtSn/C and PtSnAu/C have been synthesized and characterized. The catalysts were fabricated with modified polyol method with the amounts of 20 wt%, where the Pt : Sn ratios in the PtSn/C were 1 : 0, 4 : 1, 3 : 1, 2 : 1, 1.5 : 1, 1 : 1, 1 : 1.5 and Pt:Sn:Au ratios in the PtSnAu/C were 5 : 5 : 0, 5 : 4 : 1, 5 : 3 : 2, 5 : 2 : 3. From the XRD and TEM analysis results, the catalysts were found to have face centered cubic structure with particle size of around $1.9{\sim}2.4\;nm$. The activity in the ethanol oxidation was examined with cyclic voltammetry and the results indicated that PtSn(1.5 : 1)/C and PtSnAu(5 : 2 : 3)/C had the highest activity in each catalyst system. Further tests with single cell were performed with those catalysts. It was found that PtSn/C(1.5 : 1) exhibited the best performance while the long term stability of PtSnAu/C(5 : 2 : 3) is better than PtSn/C(1.5 : 1).

• Journal of Hydrogen and New Energy
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• v.22 no.2
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• pp.257-264
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• 2011

This study discribes performance of DEFC (Direct Ethanol Fuel Cell) utilized bio-ethanol based on fruit wastes. To produce the bio-ethanol, fruit wastes were treated at temperature $120^{\circ}C$ and 90minutes in acid pre-treatment. After pre-treatment was done, alcohol fermentation process was running. Initial alcohol concentration was 5%. Using the multi coloumn distillation system, more than 95% ethanol was distilled and each component of bio-ethanol was analyzed. In DEFC performance test, it was revealed that cell performance was much higher than that of ethanol. Comparing ethanol with mixed fuel (bio-ethanol (10%) + ethanol (90%)), the performance of ethanol was higher than that of mixed fuel. Even though the bio-ethanol from the fruit wastes is corresponded with transport ethanol standards, it thought that organic matter in bio-ethanol could be negative effect on fuel cell.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.162-162
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• 2008

세리아는 고체 산화물 연료전지(SOFC, solid oxide fuel cell)의 전해질 재료와CMP( chemical mechanical polishing) 슬러리 재료, 자동차의 3원 촉매, gas sensor, UV absorbent등 여러 분야에서 사용되고 있다. 본 연구에서는 세리아의 입자의 크기와 형상을 조절하여 성능 및 물성을 향상시켜 보다 넓은 분야의 활용을 하고자 실험을 실시하였다. 세리아 합성에 사용되는 전구체인 cerium carbonate의 특성이 세리아 분말의 물리화학적 특성에 직접적인 영향을 주기 때문에 전구체의 합성 단계에서 형상과 크기를 조절하고자 하였다. 세륨염으로 cerium nitrate hexahydrate, 균일침전반응을 할 수 있는 urea를 침전제로 사용하였다. 반응 용매의 유전상수를 조절하고 반응의 과포화도 변화를 이용하기 위하여 에탄올을 첨가하여 입자의 크기 및 형상을 조절, cubic형태의 $Ce_2O(CO_3)_2{\cdot}H_2O$ 결정상을 가지는 세리아 전구체를 합성하였다. 이렇게 생성된 전구체를 $1000^{\circ}C$에서 2시간동안 하소하여 세리아를 합성하고 반응시간, 농도, 에탄올의 함량 변화에 대해 XRD, FE-SEM, particle size analyzer, micropore physisorption analyzer 분석을 통하여 입자의 결정상과 형상, 입도 분포 및 기공분포 등을 반응인자의 변화에 따라 비교 및 해석하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.2076-2082
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• 2011

The goal of this paper is to find an operating conditions of the single direct ethanol fuel cell such as the cell temperature, and flow rates of ethanol and oxygen. To investigate the output characteristics, the electrical current increased from 0[A] with interval of 0.001[A] every 2[s], and the cell voltage was increased until the voltage became 0.05[V]. Related to the effect of the cell temperature, the output characteristics both voltage and power were increased upto 80[$^{\circ}C$] according to the increase of the current density, but those were decreased over that temperature. In addition, the optimal flow rate of ethanol in anode was identified as of 2[mL/min] due to the dependence of generation rate such as the hydrogen ion and electron. And the flow rate of oxygen in cathode was desirable to about 300[sccm/min], it might be affected by the chemical reaction rate of the water formation among hydrogen ion, electron, and oxygen. Consequently, the fundamental conditions were identified in this work, and it will be carried out to find the best conditions of membrane by the effect of the plasma surface treatment, and the effect of other catalysts except for a platinum.