• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.459-462
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• 2006

Formic acid recently attracted attention as an alternative fuel for direct liquid fuel cells(DLFCs) due to its high theoretical open circuit voltage(1.45V). In this paper, a novel chemical strategy is described for the preparation and characterization of carbon-supported and surface-alloys, which were prepared by using a successive reduction process. After preparing Au colloid nanoparticles, the deposition of Au colloid nanoparticles occurred spontaneously in the carbon black-dispersed aqueous solution. Then nano-scaled Pt layer were formed on the surface of carbon-supported Au nanoparticles. The Au-Pt[x] showed the higher electrocatalytic activity than those of the particle-alloys and commercial one (Johnson-Matthey) for the reaction of formic acid oxidation when the mass-specific currents were compared. The increased electrocatalytic activity might be attributed to the effective surface structure of surface-alloys, which have a high utilization of active materials for the surface reaction of electrode.

• 한국수소및신에너지학회논문집
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• 제22권5호
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• pp.649-655
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• 2011

Methane direct cracking can be utilized to produce $CO_x$ and $NO_x$-free hydrogen for PEM fuel cells, oil refineries, ammonia and methanol production. We present the results of a systematic study of methane direct cracking using a mixed conducting oxide, Y-doped $BaZrO_3$ ($BaZr_{0.85}Y_{0.15}O_3$), membrane. In this paper, dense $BaZr_{0.85}Y_{0.15}O_3$ membrane with disk shape was successfully sintered at $1400^{\circ}C$ with a relative density of more 93% via addition of 1 wt% ZnO. The ($BaZr_{0.85}Y_{0.15}O_3$) membrane is covered with Pd as catalyst for methane decomposition with an DC magnetron sputtering method. Reaction temperature was $800^{\circ}C$ and high purity methane as reactant was employed to membrane side with 1.5 bar pressure. The $H_2$ produced by the reaction was transported through mixed conducting oxide membrane to the outer side. In addition, it was observed that the carbon, by-product, after methane direct cracking was deposited on the Pd/ZnO-$BaZr_{0.85}Y_{0.15}O_3$ membrane. The produced carbon has a shape of sphere and nanosheet, and a particle size of 80 to 100 nm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 C
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• pp.1255-1257
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• 1997

In order to obtain key technologies for a kW class internal humidifying proton-exchange-membrane fuel cell (PEMFC) a single cell with a large electrode area has been designed and manufactured and the performance of large area membrane/electrode assemblies (MEAs) has been evaluated by using the single cell. A small area MEA made of commercial E-TEK electrode and Nafion 117 membrane showed a performance of 0.7V, $300mA/cm^2$ whereas large area MEA made of catalyst layer on carbon support and Nafion 117 showed a lower performance. To improve the performance of large MEA direct coating of catalyst was carried out on the membrane using a screen printer.

• 전기화학회지
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• 제4권4호
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• pp.172-175
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• 2001

마그네트론 스퍼터링 방법에 의하여 Nanophase 촉매층을 형성하여 Direct Methanol Fuel Cell(DMFC)에 적용하였다. 일반적인 박막 증착 방법보다 높은 압력 (Ar/He혼합기체)에서 금속 Target과 탄소 Target을 동시에 스퍼터링하여 내피온막 위에 직접 코팅함으로써 기공성 있는 PtRu혹은 Pt및 탄소입자를 포함한 새로운 구조의 촉매층을 형성하였다. 본 방법에 의하여 $1.5mg/cm^2$의 PtRu(Anode) 및 $1mg/cm^2$ Pt(Cathode) 로딩으로 2M Methanol, 1 Bar공기, $80^{\circ}C$조건에서 $45mW/cm^2$의 출력을 얻을 수 있었으며, 이는 기존의 상용방법에 의하여 제조된 전극보다 같은 조건에서 $30\%$의 성능향상을 제시한 것이다. 이는 Nanophase촉매층 구조로 인하여 초미세 분말을 적용하였고, 많은 량의 원자들이 입계에 배열하게 됨으로써 촉매반응을 원활하게 하고,연료의 공급을 효율적으로 해준 것에 기안한 것으로 판단된다. 그러므로, 본 연구의 결과를 응용할 경우 DMFC를 휴대용 전자기기에 적용함에 있어서 성능향상 및 가격경쟁력 확보에 도움을 줄 것으로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제31권2호
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• pp.331-334
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• 2010

In the present study, carbon supports mixed with purified multi-walled carbon nanotubes (MWNTs) and carbon blacks (CBs) were used to improve the cell performance of direct methanol fuel cells (DMFCs). Additionally, the effect of $O_2$ plasma treatment on CBs/MWNTs supports was investigated for different plasma RF powers of 100, 200, and 300 W. The surface and structural properties of the CBs/MWNTs supports were characterized by FT-IR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrocatalytic activity of PtRu/CBs/MWNTs catalysts was investigated by cyclic voltammetry measurement. In the experimental results, the oxygen functional groups of the supports were increased with increasing plasma RF power, while the average Pt particle size was decreased owing to the improvement of dispersibility of the catalysts. The electrochemical activity of the catalysts for methanol oxidation was gradually improved by the larger available active surface area, itself due to the introduction of oxygen functional groups. Consequently, it was found that $O_2$ plasma treatments could influence the surface properties of the carbon supports, resulting in enhanced electrocatalytic activity of the catalysts for DMFCs.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3145-3150
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• 2010

Ruthenium catalysts modified by selenium have been introduced as alternative materials to Pt in Direct methanol fuel cells (DMFCs). RuSe nano-particles were synthesized on the Vulcan XC72R carbon supports via polyol method. The prepared catalysts were electrochemically and physically characterized by cyclic voltammetry (CV,) linear sweep voltammetry, methanol tolerance test, X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energydispersive Spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Increasing the Se concentration up to 20 at % increased the electro-catalytic activity for the oxygen reduction. By increasing Se amount, Ru metallic form on the surface was increased. The $Ru_{80}Se_{20}$/C catalysts showed the highest oxygen reduction reaction (ORR) activity and outstanding methanol tolerant property in half cell tests as well as single cell test.

• 세라미스트
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• 제22권2호
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• pp.189-197
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• 2019

Direct methanol fuel cells (DMFCs) have found a wide variety of commercial applications such as portable computer and mobile phone. In a fuel cell, the catalysts have an important role and durability and efficiency are determined by the ability of the catalyst. The activity of the catalyst is determined by the structure and shape control of the nanoparticles and the dispersion of the nanoparticles and application system. The surface energy of nanoparticles determines the activity by shape control and the nanostructure is determined by the ratio of bi- and tri-metals in the alloy and core-shell. The dispersion of nanoparticles depends on the type of support such as carbon, graphen and metal oxide. In addition, a hybrid system using both optical and electrochemical device has been developed recently.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.140-145
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• 2024

High temperature co-electrolysis of H₂O-CO₂ mixtures using solid oxide cells has attracted attention as promising CO₂ utilization technology for production of syngas (H₂/CO), feedstock for E-fuel synthesis. For direct supply to E-fuel production such as hydrocarbon and methanol, the outlet gas ratio (H₂/CO/CO₂) of co-electrolysis should be controlled. In this work, current voltage characteristic test and product gas analysis were carried out under various reaction conditions which could attain proper syngas ratio.

• 한국재료학회지
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• 제25권3호
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• pp.113-118
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• 2015

To improve the methanol electro-oxidation in direct methanol fuel cells(DMFCs), Pt electrocatalysts embedded on porous carbon nanofibers(CNFs) were synthesized by electrospinning followed by a reduction method. To fabricate the porous CNFs, we prepared three types of porous CNFs using three different amount of a styrene-co-acrylonitrile(SAN) polymer: 0.2 wt%, 0.5 wt%, and 1 wt%, respectively. A SAN polymer, which provides vacant spaces in porous CNFs, was decomposed and burn out during the carbonization. The structure and morphology of the samples were examined using field emission scanning electron microscopy and transmission electron microscopy and their surface area were measured using the Brunauer-Emmett-Teller(BET). The crystallinities and chemical compositions of the samples were examined using X-ray diffraction and X-ray photoelectron spectroscopy. The electrochemical properties on the methanol electro-oxidation were characterized using cyclic voltammetry and chronoamperometry. Pt electrocatalysts embedded on porous CNFs containing 0.5 wt% SAN polymer exhibited the improved methanol oxidation and electrocatalytic stability compared to Pt/conventional CNFs and commercial Pt/C(40 wt% Pt on Vulcan carbon, E-TEK).

• 공업화학
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• 제22권2호
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• pp.167-172
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• 2011

본 연구에서는 중형기공 탄소(MCs)를 표면처리하여, 표면 관능기를 분석하고, 표면처리 효과를 조사하였다. 직접 메탄올 연료전지의 탄소지지체로 중형기공 실리카(SBA-15)를 이용한 전통적인 주형합성법을 이용하여 중형기공 탄소(MCs)를 합성하였다. 중형기공 탄소는 인산의 농도를 각각 0, 1, 3, 4, 및 5 M로 달리하여, 343 K에서 6 h 동안 처리하였다. 그리고 표면처리된 중형기공 탄소(H-MCs)에 화학적 환원방법을 이용하여 백금과 루테늄을 담지하였다. 표면처리된 탄소지지체에 담지된 백금-루테늄 촉매의 특성을 확인하기 위해 비표면적 측정장치(BET), X-선 회절분석법(XRD), X-선 광전자 분광법(XPS), 투과전자현미경(TEM), 유도결합 플라즈마 질량분석기(ICP-MS)를 이용하였다. 또한, 백금-루테늄 촉매의 전기화학적인 특성을 순환전류전압 실험으로 분석하였다. 표면분석의 결과로부터, 산소를 포함한 화학관능기가 탄소지지체에 도입된 사실을 알 수 있었다. 결론적으로, 4 M의 인산으로 표면처리한 H4M-MCs가 백금-루테늄의 균일한 분산과 함께 전기적인 촉매의 성능을 향상시키는 것을 확인할 수 있었다.