• 대한화학회지
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• 제55권1호
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• pp.92-97
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• 2011

비닐 아세트산염 합성에 대한 1족 알칼리금속 아세트산염의 촉진 효과를 조사하였다. Pd-Au/$SiO_2$ 촉매를 사용한 경우와 사용하지 않은 경우에 대해 에틸렌과 아세트산 간의 기체상 반응에 대해 생성물 선택성과 에틸렌 전환을 비교하였다. 촉진제가 촉매 표면을 안정화시켰으며, 생성물 선택성과 에틸렌 전환을 촉진하였다. 이 촉매 효과는 1족에서 위에서 아래로 내려갈수록 증가하였다. 이것은 아세트산염의 공통이온효과 때문이다.

• 한국전기전자재료학회논문지
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• 제25권11호
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• pp.922-925
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• 2012

Single crystalline Au nanowires were successfully synthesized in a tube-type furnace. The Au nanowires were grown by vapor phase synthesis technique using solid-liquid-solid (SLS) mechanism on substrates of corning glass and Si wafer. Prior to Au nanowire synthesis, Au thin film served as both catalyst and source for Au nanowire was prepared by sputtering process. Average length of the grown Au nanowires was approximately 1 ${\mu}m$ on both the corning glass and Si wafer substrates, while the diameter and the density of which were dependent on the thickness of the Au thin film. To induce a super-saturated states for the Au particle catalyst and Au molecules during the Au nanowire synthesis, thickness of the Au catalyst thin film was fixed to 10 nm or 20 nm. Additionally, synthesis of the Au nanowires was carried out without introducing carrier gas in the tube furnace, and synthesis temperature was varied to investigate the temperature effect on the resulting Au nanowire characteristics.

• Applied Science and Convergence Technology
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• 제24권4호
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• pp.117-124
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• 2015

A direct growth method of graphene on insulating substrate without catalyst etching and transfer process was developed using Au/Ni/a-C catalyst system. During the growth process, behavior of the Au/Ni catalyst was investigated using EDX, XPS, SEM, and Raman spectroscopy. The Au/Ni catalyst layer was evaporated during growth process of graphene. The graphene film was composed mono-layer flakes. The transmittance of the graphene film was ~80.6%.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.5-6
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• 2005

ZnO nanowlres (NWs) were fabricated using Au as catalyst for a method combining laser ablation cluster formation and vapor-liquid-solid (VLS) growth. The target used in synthesis was pure ZnO ceramics. Two different substrates were used; (0001)-oriented sapphires and Au-coated sapphires. The Au thin film was deposited by thermal evaporation and the thickness was about 50 ${\AA}$. ZnO NWs were only formed in case of that used catalyst metal. Field effect scanning electron microscopic (FESEM) investigation showed that the average diameter of ZnO NWs was about 70 nm and the typical lengths varied from $3{\sim}4{\mu}m$.

• Transactions on Electrical and Electronic Materials
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• 제14권3호
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• pp.156-159
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• 2013

The electrical properties of ZnO nanowire field effect transistors (FETs) have been investigated depending on various diameters of nanowires. The ZnO nanowires were synthesized with an Au catalyst on c-plane $Al_2O_3$ substrates using hot-walled pulsed laser deposition (HW-PLD). The nanowire FETs are fabricated by conventional photo-lithography. The diameter of ZnO nanowires is simply controlled by changing the thickness of the Au catalyst metal, which is confirmed by FE-SEM. It has been clearly observed that the ZnO nanowires showed different diameters simply depending on the thickness of the Au catalyst. As the diameter of ZnO nanowires increased, the threshold voltage of ZnO nanowires shifted to the negative direction systematically. The results are attributed to the difference of conductive layer in the nanowires with different diameters of nanowires, which is simply controlled by changing the catalyst thickness. The results show the possibility for the simple method of the fabrication of nanowire logic circuits using enhanced and depleted mode.

• 전기화학회지
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• 제12권3호
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• pp.282-286
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• 2009

MWNT(CNTs)를 지지체로 촉매를 합성하고 특성평가를 진행하였다. $Pt/Au/TiO_2$는 CNTs(cabon 나노 튜브) 탄소 지지체에 첨가되어 직접 메탄올 연료 전지의 성능을 개선하였다. XRD와 SEM을 통해 아나타제 $TiO_2$와 Pt/Au를 확인하였고 각각의 입자 사이즈는 200 nm와 20${\sim}$25 nm 이다. 혼성 촉매의 활성은 CV를 통해 측정되었으며 제조된 촉매는 연료전지 이용에 유망하다.

• Advances in Energy Research
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• 제2권1호
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• pp.21-31
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• 2014

The use of a microporous membrane along with Au/C catalyst for direct glycerol alkaline fuel cell was investigated. In comparison with Nafion 112, the microporous Celgard 3401 membrane provides a better cell performance due to the lower ionic resistance as confirmed by impedance spectra. The single cell using Au/C as anode catalyst prepared by using PVA protection techniques provided a higher maximum power density than the single cell with commercial PtRu/C at $18.65mW\;cm^{-2}$ The short-term current decay studies show a better stability of Au/C single cell. The higher activity of Au/C over PtRu/C was owing to the lower activation loss of Awe. The magnitude of current decay indicates a low problem of glycerol crossover from anode to cathode side. The similar performance of single cell with and without humudification at cathode points out an adequate transport of water through the microporous membrane.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.143.1-143.1
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• 2010

고분자 전해질막 연료전지(Polymer Electrolyte Membrane Fuel Cell; PEMFC)는 수소를 이용하여 전기를 발생시키는 친환경적이고 이상적인 발전장치로 고효율과 높은 전류밀도를 가지며 그 응용분야가 다양하다. 저온에서 작동하는 PEM fuel cell은 전극에서 효과적인 산화환원반응을 위해 그 촉매로 활성이 우수한 Pt(Platinum)을 사용하고 있으나, Pt의 높은 가격은 연료전지의 상용화에 걸림돌이 되고 있다. 본 연구에서는 연료전지의 Pt/C 촉매 층에서 Pt의 분산성을 높여 Pt의 담지량을 줄이고 작동 중 발생하는 Pt의 응집 현상을 방지하여 Pt의 수명을 연장시킬 목적으로, Au(gold) 나노입자를 첨가한 Pt-Au/C 복합나노촉매를 제조하였다. 본 발표에서는 합성된 Pt-Au/C 복합촉매 중 Au 첨가량이 Pt 촉매의 활성에 미치는 영향을 조사하기 위하여, 복합촉매 중에 금속(Pt+Au)의 총 함량이 30 wt.%와 40 wt.% 인 Pt-Au/C 촉매에 대하여 각각 Au 첨가량을 변화시켜, cyclic voltammetry 법에 의해 Au 첨가 효과를 조사한 결과에 대하여 보고하고자 한다. Au 나노입자를 제조하기 위한 출발 물질로는 $HAuCl_4{\cdot}4H_2O$를 이용하였고 trisodium citrate와 $NaBH_4$를 환원제로 하여, 입경이 5~8 nm 인 Au 콜로이드를 제조하였다. Pt-Au/C 복합나노촉매를 제조하기 위하여 먼저 Au/C 복합분체가 제조되었다. 0.03g의 carbon이 첨가된 carbon 현탁액에 합성된 Au 콜로이드 수용액을 첨가한 후 24시간 동안 교반하여 Au/C 복합분체를 제조하였다. 이 Au/C 복합분체에 $H_2PtCl_6{\cdot}6H_2O$ 수용액을 현탁하고 methanol 을 환원제로 사용해 Pt를 환원 석출시켜 Pt-Au/C 복합촉매를 제조하였다. Pt-Au/C 복합 나노촉매에서 Pt와 Au를 다양한 비율(3:1, 2.5:1.5, 2:2)로 합성하였으며 Pt-Au/C 복합촉매 중 금속(Pt+Au) 촉매의 총 함량은 30 wt.%와 40 wt.%로 각각 제조되었다. Au 나노입자 콜로이드의 분산성은 UV-visible spectrum의 흡광도에 의해 관찰되었고, Pt-Au/C 복합 나노촉매의 형상 및 분산성 분석은 transmission electron microscopy(TEM)에 의해 이루어졌다. 또한, 촉매의 전기화학적 특성평가는 cyclic voltammetry(CV)에 의해 조사되었다.

• Journal of Electrochemical Science and Technology
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• 제1권1호
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• pp.10-18
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• 2010

Controlled electrodeposition of dendritic nano-structured gold-platinum (AuPt) alloy onto an electrochemically pretreated carbon paper substrate was conducted in an attempt to improve catalyst utilization and to secure an electronic percolation network toward formic acid (FA) fuel cell application. The AuPt catalysts were obtained by potentiostatic deposition. AuPt catalysts synthesized as bimetallic alloys with 60% Au content exhibited the highest catalytic activity towards formic acid electro-oxidation. The origin of this high activity and the role of Au were evaluated, in particular, by XPS analysis. Polarization and stability measurements with 1 mg $cm^{-2}$ AuPt catalyst (only 0.4 mg $cm^{-2}$ Pt) showed 52 mW $cm^{-2}$ and sustainable performance using 3M formic acid and dry air at $40^{\circ}C$.

• 한국재료학회지
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• 제23권12호
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• pp.737-744
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• 2013

We demonstrated size control of Au nanoparticles by heat treatment and their use as a catalyst for single-walled carbon nanotube (SWNTs) growth with narrow size distribution. We used uniformly sized Au nanoparticles from commercial Au colloid, and intentionally decreased their size through heat treatment at 800 oC under atmospheric Ar ambient. ST-cut quartz wafers were used as growth substrates to achieve parallel alignment of the SWNTs and to investigate the size relationship between Au nanoparticles and SWNTs. After the SWNTs were grown via chemical vapor deposition using methane gas, it was found that a high degree of horizontal alignment can be obtained when the particle density is low enough to produce individual SWNTs. The diameter of the Au nanoparticles gradually decreased from 3.8 to 2.9 nm, and the mean diameter of the SWNTs also changed from 1.6 to 1.2 nm for without and 60 min heat treatment, respectively. Raman results reconfirmed that the prolonged heat treatment of nanoparticles yields thinner tubes with narrower size distribution. This work demonstrated that heat treatment can be a straightforward and reliable method to control the size of catalytic nanoparticles and SWNT diameter.