• Journal of Powder Materials
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• v.12 no.2 s.49
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• pp.117-121
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• 2005

Platinum catalysts for the DMFC (Direct Methanol Fuel Cell) were impregnated on several carbon supports and their catalytic activities were evaluated with cyclic voltammograms of methanol electro-oxidation. To increase the activities of the Pt/C catalyst, carbon supports with high electric conductivity such as mesoporous carbon, carbon nanofiber, and carbon nanotube were employed. The Pt/e-CNF (etched carbon nanofiber) catalyst showed higher maximum current density of $70 mA cm^{-2}$ and lower on-set voltage of 0.54 V vs. NHE than the Pt/Vulcan XC-72 in methanol oxidation. Although the carbon named by CNT (carbon nanotube) series turned out to have larger BET surface area than the carbon named by CNF (carbon nanofiber) series, the Pt catalysts supported on the CNT series were less active than those on the CNF series due to their lower electric conductivity and lower availability of pores for Pt loading. Considering that the BET surface area and electric conductivity of the e-CNF were similar to those of the Vulcan XC-72, smaller Pt particle size of the Pt/e-CNF catalyst and stronger metal-support interaction were believed to be the main reason for its higher catalytic activity.

• Journal of Electrochemical Science and Technology
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• v.10 no.4
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• pp.416-423
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• 2019

A novel non-enzymatic oxalic acid (OA) sensor based on the platinum/carbon black-nickel-reduced graphene oxide (Pt/CBNi-rGO) nanocomposite is reported. The nanocomposites were prepared by the ethylene glycol reduction method. Their morphology and chemical composition were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The results clearly demonstrated the formation of the Pt/CB-Ni-rGO nanocomposite. The electrocatalytic activity of the Pt/CB-Ni-rGO electrode was investigated by cyclic voltammetry. It was determined that the appropriate amount of Pt enhanced the catalytic activity of Pt for oxalic acid electro-oxidation. Moreover, the modified electrode was determined to be highly selective for oxalic acid without interference from compounds commonly found in urine including uric acid and ascorbic acid. The chronoamperometric signal gave a wide linearity range of 20 μM-60 mM and the detection limit (3σ) was found to be 2.35 μM. The proposed method showed high selectivity, stability, and good reproducibility and could be used with micro-volumes of sample for the detection of oxalic acid. Finally, the oxalic acid content in artificial and control urine samples were successfully determined by our proposed electrode.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.224-231
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• 1990

To improve the dispersion of platinum catalyst, the effects of carbon black surface treatment, solvents, surfactants, and ultrasonic homogenizing were examined. Upon introducing the hydrophilic groups acting as an anchorage center of the catalyst on the surface of carbon black by oxidation, the migrating and growing of platinum particles(or ions) during reduction could be restricted. When mixed solvents, surfactants, or ultrasonic homogenizer were used to disperse catalysts on the carbon black, the dispersion of catalyst could be improved, due to the good permeation of chloroplatinic acid through the pore of carbon black. Among the impregnation methods, the method using ultrasonic homogenizer with mixed solvent was the most excellent. Using this method the particle sized could be minimized in less than $30A^{\circ}$ and distributed homogeneously.

• Clean Technology
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• v.19 no.1
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• pp.59-64
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• 2013

Pt/carbon Electrode catalysts for PEMFC were synthesized using colloidal method. PSA (platinum sulfite acid) was used as a Pt precursor and CPA (chloroplatinic acid) was also used to replace relatively expensive PSA. Electrode catalysts prepared using PSA showed Pt particle size less than 3.5 nm and Pt yield higher than 90% in 10~40 wt% Pt loading. Electrode catalysts prepared using CPA also showed Pt particle size less than 4.4 nm and Pt yield higher than 80% in 10~40 wt% Pt loading. The MEA (membrane electrode assembly) using 20 wt% Pt/VXC72 showed equivalent I-V curve comparing with commercial electrode catalyst in single cell test.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.201-204
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• 2007

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. $TiO_2$ catalyst particles were dispersed uniformly into the Nafion solution, and then $Pt/TiO_2/Nafion$composite membrane was prepared using solution-cast method. The size, dispersion and content of the platinum had been characterized with Transmission Electron Micrograph (TEM), X-ray diffract ion (XRD) and Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES). The cell performance with the self-humidifying composite membrane was compared with a recast Nafion membrane under both humidified and dry conditions at 65 $^{\circ}C$.

• YAKHAK HOEJI
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• v.42 no.5
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• pp.494-499
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• 1998

As part of a drug discovery program to discover more effective platinum-based anticancer drugs, a series of platinum complexes of 1,2-bis(diphenylphosphino)ethane(1,2-diaminopro pane)platinum(II)dinitrate (KHPC-070) has been evaluated in vitro against various tumor cell lines and normal kidney cells. The structure of this new compound was determined by elemental analysis, infrared spectroscopy (IR) and $^{13}carbon$ nuclear magnetic resonance (NMR). With the use of nine tumor cell lines, KHPC-070 exhibited a comparable cytotoxic to cisplatin. The cytotoxicity of KHPC-070 in normal cells was quite less than that of cisplatin using 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and [$^3H$]-thymidine uptake tests in rabbit renal proximal tubular cells and human renal cortical cells. Based on these results, KHPC-070 is considered to have more selective cytotoxicity toward cancer cells than normal human/rabbit kidney cells.

• 한국전기화학회:학술대회논문집
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• 1998.10a
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• pp.93-93
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• 1998

• Bulletin of the Korean Chemical Society
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• v.17 no.7
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• pp.592-595
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• 1996

A silane dendrimer with 48 allylic end groups has been synthesized in excellent yield, via repetitive alkenylation-hydrosilation cycles. Starting with hexaallylethylenedisilane ((CH2=CHCH2)3SiCH2)2 as the core molecule (G0), a succession of alternate platinum catalyzed hydrosilation (Pt/C, 10% platinum content on active carbon) of all allyl groups with methyldichlorosilane and the allylation of all SiCl2 groups with allylmagnesium bromide in THF provided 3rd generation (G3) as carbosilane dendrimer. All the generations of dendrimer have been characterized by 1H and 13C NMR spectroscopy as well as elemental analysis.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1992.11a
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• pp.39-40
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• 1992

This paper dealt with the manufacturing of binary alloy catalyst and showed simple electrochemical method for determing catalytic activity of oxygen reduction in acid or alkaline electrolyte. The catalyst was prepared by impregnating transition metal salts on platinum or silver particles adsorbed before on carbon paper substrate. The electrochemical characteristics of the catalysts was investigated with carbon paper electrode or PTFE-boned porous electrode and then cathodic current densities and tafel slopes were compared. As a result, of all binary catalysts utilized in this work, Pt-Fe, Pt-Mo showed better oxygen reduction activity than pure platinum catalyst in acid electrolyte and Ag-Fe, Ag-Pt, and Ag-Ni-Bi-Ti catalyst did than pure silver catalyst in alkaline electrolyte. The current density of Pt-Fe electrode in acid electrolyte was one and half times higher than that of Pt electrode(~500mA/$\textrm{cm}^2$ at 0.7VvsNHE).

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.540-544
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• 2015

A bath for electrodeposition of platinum nanoparitcles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the elecrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.