• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.1925-1926
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• 2005

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.401-406
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• 2014

Metal-containing carbon nanocomposites have shown significance promise in the area of energy storage, heterogeneous catalysis and material science because of their morphology and combined properties. Phosphorus-doped carbon nanocomposites with gold nanoparticles were developed by applying a simple impregnation method and metal deposition technique. Gold-phosphorus supported carbon nanocomposites with two sized (25 and 170 nm) were prepared from economical petroleum pitch residue as the carbon source using an advanced silica template method. These nanocomposites will lead to the novel applications in the field of material science with the combined properties of gold, phosphorus and carbon. The newly prepared gold phosphorus supported carbon nanocomposites were fully characterized using a range of different physico-chemical techniques.

• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.670-677
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• 2010

A comparative study on the Au(I)-catalyzed and IBr-promoted tandem cyclization of 1,5-enyne was reported. This study provides a meaningful mechanistic insight to the concerted nature of this tandem reaction and also provides interesting applications in the synthesis of 7/5- or 8/5-fused bicycles and biaryls.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.462-465
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• 2019

Nanoscale gold particles have been intensively researched due to their potential applications in catalysis, electronics, plasmonics, and biological assays. In our study, we fabricated gold nanoparticles (NPs) that were synthesized in an aqueous environment via the reduction of $HAuCl_4$ by ascorbic acid (AC) with a sodium citrate (SC) surfactant. Highly monodispersed gold particles with sizes ranging from 123 to 184 nm were prepared in high-yield by a surfactant concentration. The structural and optical properties of the synthesized gold nanoparticles were characterized by transmission electron microscopy (TEM) and UV-vis spectroscopy. The prepared nanoparticles exhibited efficient surface-enhanced Raman scattering (SERS) properties that were dependent on their on size.

• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.683-688
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• 2010

A new and efficient Au-catalyzed alkoxycyclization of conjugated enynols offers a general entry to a wide range of highly substituted furans in good to excellent yields. These furans were subjected to diethyl acetylenedicarcoxylate to afford the interesting cycloadducts in good to excellent yields.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.281.1-281.1
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• 2013

Shape control of gold nanocrystal is still one of the most important challenges remaining to achieve geometry dependent properties. Thus far, several strategies have been developed to control the shape of nanoparticles, such as adding capping agents and diverse additives or adjusting the temperature and pH. Here, we used an already established seed-mediated method that allowed us to focus on controlling the growth stage. Cetyltrimethylammonium bromide (CTAB) and ascorbic acid (AA) were used as the ligand and the reducing agent, respectively, without using any additional additives during the growth stage. We investigated how the relative ratio of CTAB and AA concentrations could be a major determinant of nanoparticle shape over a wide concentration range of CTAB and AA. As a result, a morphology diagram was constructed experimentally that covered the growth conditions of rods, cuboctahedra, cubes, and rhombic dodecahedra. The trends in the morphology diagram emphasize the importance of the interplay between CTAB and AA. Furthermore, high-index faceted gold nanocrystal was obtained by two step seeded growth. Already synthesized cubic particles developed into hexoctahedral nanocrystal consisting of 48 identical {321} facets, which indicates that the growth of gold nanocrystal is affected by initial morphology of seed particles. The hexoctahedral gold nanoparticles can be used in catalysis and optical applications which exploiting their unique geometry. Our research can provide useful guidelines for designing various facetted geometries.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.354.1-354.1
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• 2016

Nanoporous gold (NPG) is a very promising material in various fields such as sensor, actuator, and catalysis because of its high surface to volume ratio and conducting nature. In this study, we fabricated a NPG based amperometric sensor on a glass substrate by means of co-sputtering of Au and Si. During the sputtering process, we found the optimum conditions for heat treatment to reduce the residual stress and to improve adhesion between NPG films and the glass substrate. Subsequently, Si was selectively etched from Au-Si alloy by KOH solution, which forms nanoporous structures. Scanning electron microscopy (SEM) and auger electron spectroscopy (AES) were used to estimate the structure of NPG films and their composition. By employing appropriate heat treatments, we could make very stable NPG films. We tested the performance of NPG sensor with aniline molecules, which shows high sensitivity for sensing low concentration of aniline.

• 전기화학회지
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• 제3권2호
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• pp.69-71
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• 2000

카르복시산과 이황하물 다리를 가지며 산화환원 활성이 있는 칼릭스[4]아렌을 합성하였고 그것이 은과 금 표면 위에 자발적으로 흡착하는 것을 관찰하였다. 칼릭스[4]아렌은 특이한 구조 때문에 수용액에서 알칼리 토금속이온에 선택적인 친화력을 보인다 한편 둥그런 이온 수용체를 전극 위에 고정시켰을 때 금속 이온을 포획하는 것을 전압전류법 및 분광학적인 연구를 통해 확인하였다. 아울러 EDTA와 같은 강한 킬레이트제를 이용하여 이온을 가역적으로 제거할 수 있음을 보였다.

• ETRI Journal
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• 제26권1호
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• pp.38-44
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• 2004

Searching for systems of self-assembled monolayers (SAMs) that can be used as templates for chemical lithography, we found that nitro groups on aromatic SAMs are selectively converted on Ag to amino groups by irradiation with a visible laser. 4-nitrobenzenethiol on Ag was thus converted to 4-aminobenzenethiol by irradiating it with an $Ar^+$ laser. This was evident from surface-enhanced Raman scattering (SERS) as well as from a coupling reaction forming amide bonds. The surface-induced photoreaction allowed us to prepare patterned binary monolayers on Ag that showed different chemical reactivities. Using the binary monolayers as a lithographic template, we induced site-specific chemical reactions, such as the selective growth of biominerals on either the nitro- or amine-terminated regions by adjusting the crystal-growth conditions. We also demonstrated that patterned, amine-terminated monolayers can be fabricated even on gold by using silver nanoparticles as photoreducing catalysts.

• 청정기술
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• 제26권4호
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• pp.251-256
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• 2020

The biocompatibility and plasmonic properties of Au nanoparticles make them useful for photothermal therapy, drug delivery, imaging, and many other fields. This study demonstrated a novel, facile, economic, and green synthetic method to produce gold nanoparticles. Gold nanoparticles (AuNPs) with spherical and triangular shapes were effectively synthesized using only Schisandra chenesis fruit extract as the capping and reducing agent. The shape of the AuNPs could be engineered simply by adjusting the molar concentration of HAuCl4 in the reaction mixture. The as-synthesized AuNPs were characterized using UV-VIS spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), dynamic light scattering (DLS), and energy dispersive X-ray analysis (EDXA). This study revealed that by using the HAuCl4 concentration in the AuNP synthesis, the shape and size of the AuNPs could be controlled by the concentration of HAuCl4 and Schisandra chinensis fruit extract as a surfactant. The as-synthesized AuNPs samples had sufficient colloidal stability without noticeable aggregation and showed the predominant growth of the (111) plane of face-centered cubic gold during the crystal growth. The catalytic efficiency of the AuNPs synthesized using Schisandra chenesis fruit extract was examined by monitoring the catalytic reduction of 4-nitrophenol to 4-aminophenol using Ultraviolet-visible spectroscopy (UV-Vis spectroscopy). The synthesized AuNPs showed good catalytic activity to reduce 4-nitrophenol to 4-aminophenol, revealing their practical usefulness.