• 에너지공학
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• 제2권2호
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• pp.194-199
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• 1993

인산형 연료전지에서 cathode 및 anode 전극의 반응 면적을 넓혀 전극성능을 향상시키고자 전극 촉매층에 가스 확산로를 도입하였다. 촉매층의 제작은 기체확산로로 이용하고자 제조된, 촉매가 담지되어 있지 않은 PTFE/carbon과 10w/o의 촉매가 담지된 Pt/carbon을 혼합 비율을 달리하면서 촉매 분말법으로 제작하였다. PTFE를 60w/o 담지한 PTFE(60 w/o)/carbon 분말과 Pt(10 w/o)/carbon분말을 7 : 3의 비율로 혼합하여 제조된 전극이 가장 우수한 성능을 보였다. 이들 조성을 변화시키면서 전극의 다공성과 전극성능을 비교 검토하여 본 결과 전극성능은 기체 확산로로 이용되는 macro pore와 전해질의 침투로 이용되는 micro pore 모두가 많이 형성됨에 따라 향상되었음을 알 수 있었다. 이때 전극에 담지된 백금 촉매의 양은 0.2mg/$\textrm{cm}^2$이었으며 PTFE함량은 42w/o이었다. 작동온도 15$0^{\circ}C$, 단자전압 0.7 V에서 전류밀도는 220 ㎃/$\textrm{cm}^2$이었다.

• 융복합기술연구소 논문집
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• 제9권1호
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• pp.7-12
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• 2019

The aim of this study is to improve the durability performance of catalysts for a catalytic combustor and to obtain operating conditions for stable combustion of the catalytic combustor. It was attempted to improve the durability of the catalysts by adding a promoter in order to reduce the cost of replacing Pt catalyst while maintaining stability. The main catalyst used in the study was Pt and the promoters were Ni and La. Pure Pt3/γ-Al₂O₃ catalyst without promoter was promoted to fast sintering states under harsh conditions and catalytic combustion was turned off, whereas the catalysts added La, Ni as promoter were showed relatively slow sintering states. It can be concluded that the promoter La, Ni effectively contributes to the improvement of the durability of the Pt catalyst, and it is possible to get longer durability and more stable duration than the conventional catalytic combustor.

• 한국재료학회지
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• 제30권1호
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• pp.14-21
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• 2020

Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO₂) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO₂ component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g^-1_pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g^-1_pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO₂ component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.568-571
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• 2008

A novel self-humidifying composite membrane for the proton exchange membrane fuel cell (PEMFC) at low humidity condition was developed. The Pt/$TiO_2$ catalyst particles were synthesized via supercritical impregnation methods. Pt precursor was dissolved in supercritical carbon dioxide and impregnated onto $TiO_2$ particles. Pt precursors were platinum(II) acetylacetonate, Dimethyl(1,5-cyclooctadiene) platinum(II) and we controlled the ratio of Pt to $TiO_2$. The impregnated Pt precursor was converted to $TiO_2$ supported Pt nanoparticle under various reducing conditions. Pt/$TiO_2$ catalyst particles were dispersed uniformly into the Nafion solution, and then Pt/$TiO_2$/Nafion composite membrane was prepared using solution-cast method. The self-humidifying composite membrane could minimize membrane conductivity loss under dry conditions due to the presence of catalyst and hydrophilic Pt/$TiO_2$ particles. To optimize the performance of MEA, amount of ionomer loading was controlled. And mixed catalysts were used. The cell performance of MEA was obviously improved under dry conditions at $65^{\circ}C$.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
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• pp.141-148
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• 2005

Pt/SDBC catalyst, which is used for the hydrogen-water isotopic exchange reaction, was prepared. The various properties of the catalyst, such as the thermal stability, pore structure and the platinum dispersion, were investigated. A hydrophobic Pt/SDBC catalyst which has been developed for the LPCE column of the WTRF (Wolsong Tritium Removal Facility) was tested in a trickle bed reactor. An experimental apparatus was built for the test of the catalyst at various temperatures and gas velocities.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제33회 KOSCO SYMPOSIUM 논문집
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• pp.235-241
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• 2006

Catalytic combustion is one of the suitable methods for micro power source due to high energy density and no flame quenching. Catalyst loading in the micro structured combustion chamber is one of the most important issues in the development of micro catalytic combustors. In this research, to coat catalyst on the chamber wall, two methods were investigated. First, $Al_2O_3$ was selected as a support of Pt and $Pt/Al_2O_3$ was synthesized through the alumina sol-gel procedure. To improve the coating thickness and adhesion between catalyst and substrate, heat resistant and water solvable organic-inorganic hybrid binder was used. Porous silicon was also investigated as a catalyst support for platinum. Through the parametric studies of current density and etching time, fabrication process of $1{\sim}2{\mu}m$ of diameter and about $25{\mu}m$ depth pores was confirmed. Coated substrates were test in the micro channel combustor which was fabricated by the wet etching and machining of SUS 304. Using $Pt/Al_2O_3$ coated substrate and Pt coated porous silicon substrate, conversion rate of fuel was over 95% for $H_2$/Air premixed gas.

• 한국연소학회지
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• 제11권2호
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• pp.7-14
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• 2006

Catalytic combustion is one of the suitable methods for micro power source due to high energy density and it can be applied to micro structured chamber without consideration of quenching since it is flameless combustion. Catalyst loading in the micro structured combustion chamber is one of the most important issues in the development of micro catalytic combustors. In this research, to coat catalyst on the chamber wall, two methods were investigated. First, $Al_2O_3$ was selected as a support of Pt and $Pt/Al_2O_3$ was synthesized through the alumina sol-gel procedure. To improve the coating thickness and adhesion between catalyst and substrate, heat resistant and water solvable organic-inorganic hybrid binder was used. Porous silicon was also investigated as a catalyst support for platinum. Through the parametric studies of current density and etching time, fabrication process of $1{\sim}2{\mu}m$ of diameter and about $25{\mu}m$ depth pores was confirmed. Coated substrates were test in the micro channel combustor which was fabricated by the wet etching and machining of SUS 304. Using $Pt/Al_2O_3$ coated substrate and Pt coated porous silicon substrate, conversion rate of fuel was over 95 % for $H_2/Air$ premixed gas.

• 분석과학
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• 제18권2호
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• pp.120-129
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• 2005

VOC는 대기오염의 주원인으로서 인식되어왔다. 촉매산화는 저온에서 높은 효율을 나타내기 때문에 VOCs 제거를 위한 가장 중요한 처리기술중 하나이다. 이 연구에서는 $TiO_2$ 담체에 Pt, Ir 그리고 Pt-Ir을 담시지켜 촉매를 제조하였다. 금속 분산에 따르면 $H_2O-H_2$ 처리방법이 사용되었고, 반응물로서 Xylene,Toluene 그리고 MEK을 사용하였다. 단일 또는 두 가지 이상의 촉매들은 함침법에 의해 준비하였고, XRD, XPS, TEM 분석을 통하여 특성화하였다. 그 결과 Pt 촉매는 Ir 촉매에 비해 더 높은 전환율을 나타내었고, Pt-Ir 촉매는 가장 높은 전환율을 나타내었다. $H_2O-H_2$ 처리한 촉매들은 처리하지 않은 것보다 VOCs 전환율이 높았다. VOCs 산화에서, Pt-Ir 촉매는 다양한 활성점을 나타내었고 그것은 Pt의 metal 영역을 강화시켰다. 따라서 두 가지 금속으로 이루어진 촉매가 단일 금속으로 이루어진 촉매에 비해 VOCs 전환율이 더 높았다. $H_2O-H_2$ 처리가 Pt 입자의 분산에서 형태에 영향을 미쳤다. 동역학적으로 VOCs 산화는 1차 반응이다. $H_2O-H_2$ 처리한 촉매들의 활성화에너지가 처리하지 않은 것들보다 낮았다. 이 연구에서 Pt에 Ir을 소량첨가함으로써 VOCs 산화반응에 효과적이었다.

• 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.

• 전기화학회지
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• 제11권4호
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• pp.313-318
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• 2008

본 연구에서는 백금의 입자크기가 내구성과 활성에 미치는 영향을 고찰하였다. 상용 Pt/C의 열처리를 통해 백금 입자 크기를 $3.5{\sim}9\;nm$로 조절하였고, XRD와 TEM을 통해 이를 확인하였다. 촉매의 내구성 분석을 위해 가속 실험을 실시하였고, 촉매 활성 측정을 위해 산소환원반응 실험을 하였다. 백금의 입자크기를 증가시킬수록 내구성은 향상되었으나 촉매의 활성이 저하되었다. 즉 촉매의 내구성과 활성은 반비례관계가 성립된다는 것을 확인하였다. 그리고 저하된 촉매 활성과 내구성을 향상시키기 위해, 합금 촉매를 사용하였다.상용 Pt/C의 최대 전력 밀도는 약 $507.6\;mV/cm^2$ 이고, PtCo/C 합금촉매는 $585.8\;mV/cm^2$이었다. 전기화학적 표면적은 상용 Pt/C는 약 60%정도 감소하였고, PtCo/C 합금촉매는 약 24%정도의 감소율을 나타냈다. 따라서 백금의 입자 크기 조절과 합금화를 통해 백금의 내구성과 활성을 동시에 높일 수 있었다.