• 공업화학
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• 제18권5호
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• pp.467-474
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• 2007

팔라듐과 금 나노입자 등이 첨착된 높은 비표면적을 갖는 Polyacrylonitrile (PAN)계 활성탄소섬유(ACF: Activated Carbon Fiber)를 제조하였다. 여러 첨착 ACF에 대하여 BET, FE-SEM, TEM, XPS 등으로 비표면적과 기공부피, 미세구조, 시간에 따른 산소관능기의 표면변화를 관찰하였으며 $SO_2$에 대한 흡착성능을 연구하였다. 그 결과 첨착과정으로 인하여 총 기공부피 대비 미세기공 부피는 95.5%에서 30.5~43.7%로 대부분 감소하였으며, 산소관능기의 표면변화는 대기중에서 시간이 경과함에 따라 나노입자보다 금속염의 산소관능기 변화가 컸음을 알 수 있었다. 또한 Au 나노입자와 금속염을 첨착한 ACF의 $SO_2$ 파과시간은 무첨착 ACF에 비하여 크게 변하지 않았으나, 100 ppm의 Pd 나노입자를 첨착한 ACF는 $SO_2$ 파과시간이 880 s로 흡착성능이 우수하였다. 이러한 결과로 볼 때 $SO_2$ 흡착성능은 시간에 따른 산소관능기의 표면 변화와 연관성이 있다고 볼 수 있으며, PAN계 활성탄소섬유에 적정한 농도의 Pd 나노입자 첨착은 촉매작용으로 인하여 $SO_2$ 흡착 성능을 증가시키는 것으로 판단된다

• Advances in materials Research
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• 제3권4호
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• pp.199-216
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• 2014

Noble metal nanoparticles (mainly Au, Ag, Pt and Pd) have received enormous attention owing to their unique and fascinating properties. In the past decades, many researchers have reported methods to control the shape and the size of these noble metal nanoparticles. They have consequently demonstrated outstanding and tunable properties and thus enabled a variety of applications such as surface plasmonics, photonics, diagnostics, sensing, energy storage and catalysis. This paper focuses on the recent advances in the solution-phase synthesis of shape- and size-controlled noble metal nanoparticles. The strategies and protocols for the synthesis of the noble metal nanoparticles are introduced with discussion of growth mechanisms and important parameters, to present the general criteria needed for producing desirable shapes and sizes. This paper reviews their remarkable properties as well as their shape- and size- dependence providing insights on the manipulation of shape and size of metal nanoparticles, necessary for appropriate applications. Finally, several applications using the shape- and size-controlled noble metal nanoparticles are highlighted.

• 한국분말재료학회지
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• 제14권3호
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• pp.165-172
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• 2007

The purpose of this study was to analyze the sintering characteristics of gold and silver nanoparticles. In this study, gold and silver nanoparticles were prepared by using Inert Gas Cndensation (IGC). The sintering temperatures for gold and silver nanoparticles were $100{\sim}1000^{\circ}C\;and\'100{\sim}500^{\circ}C$, respectively. The sintering characteristics of gold and silver nanoparticles prepared by IGC were evaluated by X-ray diffraction(XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Gold and silver nanoparticles with the size of $1{\sim}100\;nm\;and\;10{\sim}100\;nm$, respectively, were obtained. The size of sintered gold and silver nanoparticles increased with an increase in the sintering temperature. XRD data showed that silver nanoparticles were similar with polycrystal single-phase.

• 한국결정성장학회지
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• 제25권6호
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• pp.280-284
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• 2015

Au doped $TiO_2$ nanoparticles have been synthesized using a reverse micelle technique combined with metal alkoxide hydrolysis and condensation. Au doped $TiO_2$ was coated with glass substrate. The size of the particles and thickness of the coating can be controlled by manipulating the relative rates of the hydrolysis and condensation reaction of TTIP within the micro-emulsion. The average size of synthesized Au doped $TiO_2$ nanoparticle was about in the size range of 15 to 25 nm and the Au particles formed mainly the range of 2 to 10 nm in diameter. The effect of synthesis parameters, such as the molar ratio of water to TTIP and the molar ratio of water to surfactant, are discussed. The synthesized nanopaticles were coated on glass substrate by a spin coating process. The thickness of thin film was about 80 nm. The degradation of MB on a $TiO_2$ thin film was enhanced over 20 % efficiency by the incorporation of Au.

• Environmental Engineering Research
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• 제21권1호
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• pp.99-107
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• 2016

The adsorption of inorganic mercury, Hg (II), in aqueous solution has been investigated to evaluate the effectiveness of synthesized gold (Au) nanoparticle-coated silica as sorbent in comparison with activated carbon and Au-coated sand. The synthesis of the Au-coated silica was confirmed by x-ray diffraction (Bragg reflections at $38.2^{\circ}$, $44.4^{\circ}$, $64.6^{\circ}$, and $77.5^{\circ}$) and the Au loading on silica surface was $6.91{\pm}1.14mg/g$. The synthesized Au-coated silica performed an average Hg adsorption efficiency of ~96 (${\pm}2.61$) % with KD value of 9.96 (${\pm}0.32$) L/g. The adsorption kinetics of Hg(II) on to Au-coated silica closely follows a pseudo-second order reaction where it is found out to have an initial adsorption rate of $4.73g/{\mu}g/min/$ and overall rate constant of $4.73{\times}10^{-4}g/{\mu}g/min/$. Au-coated silica particles are effective in removing Hg (II) in aqueous solutions due to their relatively high KD values, rapid adsorption rate, and high overall efficiency that can even decrease mercury levels below the recommended concentrations in drinking water.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.140.2-140.2
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• 2013

Strong metal-support interaction effect is an important issue in determining the catalytic activity for heterogeneous catalysis. In this work, we report the catalytic activity of $Au/TiO_2$, $Au/Al_2O_3$, and $Au/Al_2O_3-CeO_2$ nanocatalysts under CO oxidation fabricated by arc plasma deposition (APD), which is a facile dry process with no organic materials involved. These catalytic materials were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and $N_2$-physisorption. Catalytic activity of the materials has measured by CO oxidation using oxygen, as a model reaction, in a micro-flow reactor at atmospheric pressure. Using APD, the catalyst nanoparticles were well dispersed on metal oxide powder with an average particle size (3~10 nm). As for catalytic reactivity, the result shows $Au/Al_2O_3-CeO_2$ nanocatalyst has the highest catalytic activity among three samples in CO oxidation, and $Au/TiO_2$, and $Au/Al_2O_3$ in sequence. We discuss the effects of structure and metal-oxide interactions of the catalysts on catalytic activity.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.365-370
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• 2014

For real-time monitoring of colloidal nanoparticles (NPs) in aqueous media, a light sheet type dark-field microscopy system combined with a microfluidic concentration gradient generator (${\mu}FCGG$-LSDFM) was developed. Various concentrations of colloidal Au NPs were simultaneously generated with the iFCGG and characterized with the LSDFM setup. The number concentrations and hydrodynamic size distributions were measured via particle counting and tracking analysis (PCA and PTA, respectively) approaches. For the 30 nm Au NPs used in this study, the lower detection limit of the LSDFM setup was 3.6 ng/mL, which is about 400 times better than that of optical density measurements under the same ${\mu}FCGG$ system. Additionally, the hydrodynamic diameter distribution of Au NPs was estimated as $39.7{\pm}12.2nm$ with the PTA approach, which agrees well with DLS measurement as well as the manufacturer's specification. We propose this ${\mu}FCGG$-LSDFM setup with features of automatic generation of NP concentration gradient and real-time monitoring of their physicochemical characteristics (e.g., number concentration, and hydrodynamic size distribution) as an important component of future high-throughput screening or high-content analysis platforms of nanotoxicity.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.731-736
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• 2014

An organic junction transistor with a vertical structure based on an active layer of poly(3-hexylthiophene) was fabricated by facile micro-contact printing combined with the Langmuir-Schaefer technique, without conventional e-beam or photo-lithography. Direct printing and subsequent annealing of Au-nanoparticles provided control over the thickness of the Au electrode and hence control of the electrical contact between the Au electrode and the active layer, ohmic or Schottky. The junction showed similar current-voltage characteristics to an NPN-type transistor. Current through the emitter was simply controllable by the base voltage and a high transconductance of ~0.2 mS was obtained. This novel fabrication method can be applied to amplifying or fast switching organic devices.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2009년도 Korea Superconductivity Society Meeting 2009
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• pp.49-49
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• 2009

• Korean Chemical Engineering Research
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• 제50권5호
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• pp.795-801
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• 2012

가장 널리 이용되고 있는 금속나노입자 중 금과 은을 친환경용매인 RTILs (room temperature ionic liquids)를 이용하여 제조하고자 하였다. 본연구에서는 두 종류의 이온성 액체, 즉 비수용성인 [BMIM][$PF_6$] (1-Butyl-3-methylimidazolium hexafluorophosphate)과 수용성인 [BMIM][Cl](1-Buthy-3-methylimdazolium chloride)를 이용하여 리간드로 안정화된 금속 나노입자를 제조하고자 하였다. 이 중 [BMIM][Cl]은 논연구에서 Dupont 등의 방법으로 직접 합성하여 물성 분석 후 사용하였으며, [BMIM][$PF_6$]은 완제품을 구입하여 사용하였다. 금과 은의 나노입자들을 습식으로 제조하는 경우의 Brust et al.[6]의 방법이 널리 알려져 있으며, 본 연구에서도 이를 기초로 하여 나노입자를 제조하였다. [BMIM][$PF_6$]로 나노입자 제조시는 이 용매가 물에 녹지 않으므로 기본적으로는 유기용매 대신 [BMIM][$PF_6$]를 사용하는 것 외에는 Brust 등과 같은 방법제조하였다. [BMIM][Cl]로 나노입자를 제조하는 경우는 이 용매가 수용성이므로 상전이제와 ethanol은 사용하지 않고 입자를 제조하였다. 이렇게 얻어진 나노입자들의 경우 [BMIM][$PF_6$]로 합성한 경우는 FT-IR, UV-vis, TEM 그리고 TGA 분석을 통하여 Brust 등이 합성한 경우와 유사한 결과를 얻었지만, [BMIM][Cl]의 경우는 형태학적으로 다른 나노입자를 얻었다. 기존의 나노입자를 제조하는 과정에서 이용되는 유기용매를 이용하는 방법을 그린용매인 이온성 액체로 대체할 수 있다는 가능성을 확인할 수 있었고, 이온성 액체의 특성에 따라서 형태학적으로 다른 입자를 얻을 수 있었으나, 이 부분은 추후 더 많은 연구가 필요하다.