• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.118-123
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• 2008

In the present study, the effect of oxyfluorination treatment on multi-walled nanotubes (MWNTs) supports was investigated by analyzing surface functional groups. The surface characteristics were determined by Fourier transformed-infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). After the deposition of platinum nanoparticles on the above treated carbon supports, a crystalline size and a loading level had been investigated. Electrochemical properties of the treated MWNTs-supported Pt (Pt/MWNTs) catalysts were analyzed by current-voltage curve measurements. From the results of surface analysis, an oxygen and fluorine-containing functional group had been introduced to the surface of carbon supports. The oxygen and fluorine contents were the highest value at the treatment of 100 temperature. The Pt/100-MWNTs showed the smallest particle crystalline size of 3.5 nm and the highest loading level of 9.4% at the treatment of 100 temperature. However, the sample treated at the higher temperature showed the larger crystalline size and the lower loading level. This indicated that the crystalline size and the loading level could be controlled by changing the temperature of oxyfluorination treatment. Accordingly, an electrochemical activity was enhanced by increasing the temperature of treatment upto 100, and then decreased in the case of 200 and 300. The highest specific current density of 120 mA/mg had been obtained in the case of Pt/100-MWNTs.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.331-334
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• 2010

In the present study, carbon supports mixed with purified multi-walled carbon nanotubes (MWNTs) and carbon blacks (CBs) were used to improve the cell performance of direct methanol fuel cells (DMFCs). Additionally, the effect of $O_2$ plasma treatment on CBs/MWNTs supports was investigated for different plasma RF powers of 100, 200, and 300 W. The surface and structural properties of the CBs/MWNTs supports were characterized by FT-IR, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and inductive coupled plasma-mass spectrometer (ICP-MS). The electrocatalytic activity of PtRu/CBs/MWNTs catalysts was investigated by cyclic voltammetry measurement. In the experimental results, the oxygen functional groups of the supports were increased with increasing plasma RF power, while the average Pt particle size was decreased owing to the improvement of dispersibility of the catalysts. The electrochemical activity of the catalysts for methanol oxidation was gradually improved by the larger available active surface area, itself due to the introduction of oxygen functional groups. Consequently, it was found that $O_2$ plasma treatments could influence the surface properties of the carbon supports, resulting in enhanced electrocatalytic activity of the catalysts for DMFCs.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.727-734
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• 2017

The electrochemical conversion of $CO_2$ is one of the methods for reducing $CO_2$. Four materials (Ag, Ni, Pt, and Ir) were selected as the electrodes. The electrochemical conversion was performed under a cell voltage of 4.0 V at $600^{\circ}C$. The amounts of $CO_2$ reduction and carbon production were at the highest for Ag, followed by, Pt, Ni, and then Ir. The produced carbon samples were analyzed by thermogravimetric analysis and XRD. The thermogravimetric analysis results indicated that all the carbon produced at each electrode exhibited similar thermal reactivity. The XRD results showed that the crystallization of carbon was different depending on the electrode utilized. Although electrochemical conversion was the highest for the Ag electrode, a loss of material accompanied it. Therefore, for this study, the optimal electrode is Pt, taking into account reactivity and material losses.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.300-306
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• 2014

In this study, we investigated the noble metal catalysts for HCHO removal at room temperature. These catalysts were characterized by XRD, FT-IR, CO-chemisorption. As a result, Pt and Pd based catalysts prepared by the reduction treatment showed the superior HCHO oxidation ability at room temperature. When the catalysts were prepared using $TiO_2$ support, which is well known as the reducing support, showed the superior activity. Also, the activity decreased by the agglomeration of active metal with increasing the reduction time. In case of reduction catalysts, it has been confirmed that the desorption and adsorption ability properties of HCHO is excellent at room temperature.

• Biomolecules & Therapeutics
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• v.11 no.2
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• pp.91-98
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• 2003

A new series of highly water soluble platinum(II) complexes[Pt(II)(DL-2-hydroxy-3-methylbutyrate)(trans-l-1,2-dimninocyc1ohexane)] (PC-1) and [Pt(II)DL-2-hydroxy-3-methylbutyrate](cis-1,2-diaminocyclohexane)](PC-2) were synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared(IR), $^{13}C$-nuclear magnetic resonance (NMR)]. In vitro antitumor activity of new Pt(II)complexes was tested against MKN-45, MKN/ADM and MKN/CDDP human gastric adenocarcinoma cell lines using colorimetric MTT[3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazoliumbromide] assay for cell survival and proliferation. PC-1 and PC-2 showed active against MKN-45/P, MKN/ADM and MKN/CDDP human gastric cancer cell lines, and the antitumor activity of these compounds were comparable or superior to that of cisplatin. The nephrotoxicities of PC-1 and PC-2 were found quite less then that of cisplatin using MTT and [$^3H$] thymidine uptake tests in rabbit proximal tubule cells, human kidney cortical cells human renal cortical tissues. Based on these results, these novel platinum(II) complex compounds(PC-1 ＆ PC-2) represent a valuable lead in the development of the new anticancer chemotherapeutic agents capable of improving antitumor activity and low nephrotoxicity.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.369-377
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• 1999

A new series of highly water soluble platinum(II) complexes {Pt(II)[1,3-bis(phenylthio) propane](trans- -1,2-diaminocyclohexane) (PC-1) and Pt(II)[1,3-bis-(phenythio)propane] cis-1,2-diaminocyclohexane(PC-2)} were synthesized, and characterized by their elemental analysis and by various spectroscopic techniques[infrared(IR), 13C-nuclear magnetic resonance (NMR)]. In vitro antitumor activity of new Pt(II) complexes was tested against P-388 and L-1210 mouse lymphocytic leukemia cell lines, PC-14 / P, PC-14/ADM and PC-14 / CDDP human pulmonary adenocarcinima, DU-145 human prostate carcinoma, HT-1376 human bladder carcinoma, ZR-75-1 human breast carcinoma, MKN-45/P and MKN-45/CDDP human gastric adenocarcinoma cell lines using colorimetric MTT[3-(4,5-dimethyl thiazol-2-yl)-2.5-diphenyltetrazoliumbromide] assay for cell survival and proliferation. PC-1 showed active against L-1210, P-388 leukemia, human lung, stomach, prostate, bladder and breast cancer cell lines, and the antitumor activity of these compounds were comparable or superior to those of PC-2 and displatin. The nephrotoxicities of PC-1 and PC-2 were found quite less than that of cisplatin using MTT and [3H] thymidine uptake in rabbit proximal tubule cells and human kidney cortical cells. Based on these results, this novel platinum (II) complex compound (PC-1) represents a valuable lead in the development of a new anticancer chemotherapeutic agent capable of improving antitumor activity and low nephrotoxicity.

• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.147-154
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• 1994

The imperfections of LiTaO3 crystals grown from the Pt-Rh and the Ir crucible were investigated with X-ray diffraction, optical and electron microscope. The growth direction was <100>h and the plane parallel to the plane connecting two main growth ridges was (012)h which would be the main cleavage plane. The dislocation density in the specimen cut parallel to (012)h plane increased with polishing time and the inverted ferroelectric microdomains were induced based on this dislocations. Such imperfections as 180$^{\circ}$ domains, microcracks, dislocations and stacking faults. could be found in the LiTaO3 crytals. The crystal contaminated with lots of Rh form Pt-Rh crucible during the crystal growing under air atmosphere contained more imperfections. The main cleavage plane and subgrain boundary parallel to its growing axis might be the main source of reducing the mechnical strength during the wafering process.

• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.39-46
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• 1994

LiTaO3 single crystals were growth without cracking using Pt-Rh crucible and Ir crucible. The starting composition to get the melt of congruent melting composition, which has been dependent upon the experimental procedure, was taken after fixing the total growing process by the result of preliminary experiments. The Rh contamination from the Pt-Rh crucible was to be neglected if the crystal had been grown under inert atmosphere, which resulted in the crystal color being slightly yellow. This color was decolored after 24 hour's annealing at 1200℃ under air atmosphere. The optimum conditions for the crystal growing and the diameter control were so dependent upon the crucible material in spite of using the crucible of the same size. The liquid-solid interface of LiTaO3 crystal of 1" diameter has been flat if the rotation speed was 45rpm.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.669-673
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• 1994

Coordination isomers of cis-(N-N)Pt(Glu) prepared by reaction of cis-(N-N)Pt($SO_4$) (N-N=2$NH_3$, ethylenediamine(en),(R,R)-1,2-diaminocyclohexane (DACH), N,N,N',N'-tetramethylethylenediamine (TMEDA)) with barium glutamate in water have been monitored and characterized by $^1H-NMR$, $^{13}C-NMR$, IR, and mass spectra. The reaction at room temperature affords the mixture of O,O'-and N, ${\alpha}$ O-chelated platinum(II) complexes. The O,O'-chelate initially formed isomerized to N,${\alpha}$O-chelate on standing for a long time or increasing temperature. The ratio of the two isomers at room temperature depends on the nature of the nitrogen donor coligand (N-N).

• Analytical Science and Technology
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• v.6 no.1
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• pp.107-119
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• 1993

The purpose of this study is to investigated the elution behavior of platinoid metal acetylacetonates, which is the key to elucidate their retention mechanism and optimize their RPLC separation conditions. The retention data of four platinoid metal acetylacetonates have been measured on four different columns in methanol-water and acetonitrile-water systems. The retention of uncharged platinoid metal acetylacetonates is interpreted by solvophobic effect. The retention of platinoid metal acetylacetonates is also greatly influenced by the geometric structure of the complexes. The square planar chelates, $Pd(acac)_2$, $Pt(acac)_2$, are retained longer than the octahedral chelates, $Rh(acac)_3$, $Ir(acac)_3$. It is likely due to that square planar chelates show greater interaction with nonpolar stationary phase than octahedral chelates. The results of van't Hoff plots have shown that platinoid metal acetylacetonates is operated on the same retention mechanism in the temperature range of $25{\sim}45^{\circ}C$. The study of the retention mechanism by the enthalpy-entropy compensation phenomenon has indicated that the retention mechanism of octahedral chelates and square planar chelates do not vary with the composition change of methanol-water mobile phase, respectively. In acetonitrile-water mobile phase, however, the retention mechanism is observed to be more complicated. Optimum condition for the separation of four platinoid metal acetylacetonates is found to be 40% methanol, polymeric C18 column, and $45^{\circ}C$.