• Journal of Hydrogen and New Energy
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• v.30 no.6
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• pp.549-555
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• 2019

Electrocatalysis of oxygen reduction reaction (ORR) using Pt nanoparticles or bimetal on carabon was studied. Currently, the best catalyst is platinum, which is a limited resource and expensive to commercialize. In this paper, we investigated the cheaper and more active electrocatalysts by making Pt nanoparticles and adding 3D transition metal such as copper. Electrocatalysts were obtained by chemical reduction based on ethylene glycol solutions. Elemental analysis and particle size were confirmed by XRD and TEM. The electrochemical surface area (ECSA) and activity of the catalyst were determined by electrochemical techniques such as cyclic voltammetry and linear sweep voltammetry method. The commercialized Pt support on carbon (Pt/C, JM), synthesis Pt/C and synthesis Pt3Cu1 alloy nanoparticles supported on carbon were compared. We confirmed that the synthesized Pt3-Cu1/C has high electrochemical performance than commercial Pt/C. It is expected to develop an electrocatalyst with high activity at low price by increasing the oxygen reduction reaction rate of the fuel cell.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.627-634
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• 2023

Graphitic carbon nitride (g-C₃N₄) has attracted considerable attention since its discovery for its catalysis of water splitting to hydrogen and oxygen under visible light irradiation. However, pristine g-C₃N₄ confers only low photocatalytic efficiency and requires surface cocatalysts to reach moderate activity due to a lack of accessible surface active sites. Inspired by the high specific surface area and superior electron transfer of graphene, we developed a strongly coupled binary structure of graphene and g-C₃N₄ aerogel with 3D porous skeleton. The as-prepared 3D structure photocatalysts achieve a high surface area that favors efficient photogenerated charge separation and transfer, enhances the light-harvesting efficiency, and significantly improves the photocatalytic hydrogen evolution rate as well. The photocatalyst performance is observed to be optimized at the ratio 3:7 (g-C₃N₄:GO), leading to photocatalytic H₂ evolution of 16125.1 mmol. g^-1. h^-1 under visible light irradiation, more than 161 times higher than the rate achieved by bulk g-C₃N₄.

• The Korean Journal of Pharmacology
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• v.29 no.2
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• pp.283-295
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• 1993

Pt-complexes is currently one of the most compounds used in the treatment of solid tumors. However, its used is limited by severe side effects such as renal toxicity. Our platinum-based drug discovery program is aimed at developing drugs capable of diminishing toxicity and improving antitumor activity. We synthesized new Pt (II) complex analogues containing 1, 2-diaminocyclohexane (dach) as carrier ligand and 1, 3-bis (diphenylphosphino) propane (DPPP)/1,2-bis (diphenylphosphino) ethane (DPPE) as a leaving group. Furthermore, nitrate was added to improve the solubility. A new series of (KHPC-001) [Pt (trans-1-dach)(DPPP)] $2NO_3$ and (KHPC-002) [Pt (trans-1-dach)(DPPE)] $2NO_3$ were synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (IR), $^{13}carbon$ nuclear magnetic resonance (NMR)]. KHPC-001 and KHPC-002 demonstrated acceptable antitumor activity aganist P-388, L-1210 lymphocytic leukemia cells and significant activity as compared with that of cisplatin. The toxicity of KHPC-001 and KHPC-002 was found quite less than that of cisplatin using MTT, $[^3H]$ thymidine uptake and glucose consumption tests in rabbit proximal tubule cells and human kidney cortical cells.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.188-190
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• 2007

The MEA with the catalyst layer containing PtRu black and 60 wt. %Pt/C as their anode and cathode catalysts. For find to effect of carbon support, the MEA with platinum black for cathode catalyst was fabricated. The performance of the MEA with the catalyst layer containing (PtRu black:60 wt.% Pt/C) as their anode and cathode catalyst has shown competitively higher value than the performance of the MEA with the catalyst layer containing (PtRu black:Pt black) as their anode and cathode catalyst.

• Applied Microscopy
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• v.43 no.2
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• pp.88-97
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• 2013

Technical investigation to figure out the problems arising during in-situ heating electron backscatter diffraction (EBSD) analysis inside scanning electron microscopy (SEM) was carried out. EBSD patterns were successfully acquired up to $830^{\circ}C$ without degradation of EBSD pattern quality in steels. Several technical problems such as image drift and surface microstructure pinning were taking place during in-situ experiments. Image drift problem was successfully prevented in constant current supplying mode. It was revealed that the surface pinning problem was resulted from the $TiO_2$ oxide particle formation during heating inside SEM chamber. Surface pinning phenomenon was fairly reduced by additional platinum and carbon multi-layer coating before in-situ heating experiment, furthermore was perfectly prevented by improvement of vacuum level of SEM chamber via leakage control. Plane view in-situ observation provides better understanding on the overall feature of recrystallization phenomena and cross sectional in-situ observation provides clearer understanding on the recrystallization mechanism.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.386.1-386.1
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• 2014

The ionic polymer-metal composite (IPMC), a type of electro-active polymer material, has received enormous interest in various fields such as robotics, medical sensors, artificial muscles because it has many advantages of flexibility, light weight, high displacement, and low voltage activation, compare to traditional mechanical actuators. Mostly noble metal materials such as gold or platinum were used to form the electrode of an IPMC by using electroless plating process. Furthermore, carbon-based materials, which are carbon nanotube (CNT) and reduced graphene-CNT composite, were used to alter the electrode of IPMC. To form the electrode of IPMC, we employ the synthesized graphene on copper foil by chemical vapor deposition method and use the transfer process by using a support of PET/silicone film. The properties of graphene were evaluated by Raman spectroscopy, UV/Vis spectroscopy, and 4-point probe. The structure and surface of IPMC were analyzed via field emission scanning electron microscope. The fabricated IPMC performance such as displacement and operating frequency was measured in underwater.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1996-2002
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• 2007

The redox behavior of a [Ni6(μ3-Se)2(μ4-Se)3(Fe(η 5-C5H4P-Ph2)2)3] (= [Ni-Se-dppf], dppf = 1,1-bis(diphenylphosphino) ferrocene) cluster was studied using platinum (Pt) and glassy carbon electrodes (GCE) in nonaqueous media. The cluster showed electrochemical activity at the potential range between +1.6 and ?1.6 V. In the negative region (0 to ?1.6 V), the cluster exhibited two-step reductions. The first step was one-electron reversible, while the second step was a five-electron quasi-reversible process. On the other hand, in the positive region (0 to +1.6 V), the first step involved one-electron quasi-reversible process. The applicability of the cluster was found towards the electrocatalytic reduction of CO2 and was evaluated by experiments using rotating ring disc electrode (RRDE). RRDE experiments demonstrated that two electrons were involved in the electrocatalytic reduction of CO2 to CO at the Se-Ni-dppf-modified electrode.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.123-141
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• 1989

The purpose of this study was to investigate the tendency of color change of ceramic, and its mechanism un der the influence of Pd-Ag alloy. The specimens were made by firing porcelain on tile metal plates cast with Au-Pt alloy, Pd-Cu alloy and Pd-Ag alloy. In the case of Pd-Ag alloy, specimens were fired under three different conditions as follows, 1) without protection, 2) protection with ceramic metal conditioner, 3) protection with carbon block. For the specimens of element analysis, a barrier was constructed with platinum foil between metal plate and ceramic. Color change was measured with colorimeter and elemental changes in ceramic were calculated with DC argon plasma emission spectrophotometer. The results were as follows : 1. Color change of ceramic by Pd-Ag alloy was negligible in hue, but decreased in value and increased in chroma (yellow discoloration). 2. Color change of ceramic by Pd-Ag alloy was appeared through vapor transport mechanism. 3. As the protection method for the color change of ceramic by Pd-Ag alloy, application of ceramic metal conditioner was superior to utilization of carbon block.

• Journal of Hydrogen and New Energy
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• v.33 no.3
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• pp.202-208
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• 2022

Pt-Ni nanocatalysts were loaded on carbon black by spontaneous reduction reaction of platinum (II) acetylacetonate and nickel (II) acetylacetonate, and they were characterized by transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), energy dispersive x-ray analyzer (EDS), BET surface area and fuel cell test station. The distribution of the Pt and Ni nanoparticles was observed by TEM, and the loading weight of Pt-Ni nanocatalysts on the carbon black was measured by TGA. The elemental ratio of Pt and Ni was estimated by EDS. It was found that the loading weight of Pt-Ni nanoparticles was 5.54 wt%, and the elemental ratio of Pt and Ni was 0.48:0.35. Specific surface area was measured by BET analysis instrument and I-V characteristics were estimated.

• Journal of Surface Science and Engineering
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• v.36 no.3
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• pp.229-233
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• 2003

Boron-Carbon-Nitrogen (B-C-N) system is an attractive ternary material since it has not only an extremely high hardness but also a number of other prominent characteristics such as chemical inertness, elevated melting point, and low thermal expansion. In this paper, the corrosion behavior of B-C-N thin films in aqueous solution was investigated B-C-N films with different composition were deposited on a platinum plate by magnetron sputtering in the thickness range of 150-280 nm. In order to understand effect of pH of solutions, $BC_{2.\;4}N$ samples were immerged in 1M HCl, 1M NaCl, and 1M NaOH solution at 298k, respectively. BCN samples with different carbon contents were exposed to 1M NaOH solutions to investigate effect of chemical composition on corrosion resistance. Corrosion rates of samples were measured by ellipsometry, From results, optical constant of $BC_{2,\;4}N$ films was found to be $N_2=2.110-0.295i$. The corrosion rates of $Bi_{1.\;0}C_{2.\;4}N_{1.\;0}$ films were NaOH>NaCl>HCl in orders. With increasing carbon content in B-C-N films, the corrosion resistance of B-C-N films was enhanced. The lowest corrosion rate was obtained for $B_{1.\;0}C_{4.\;4}N_{1.\;9}$ film.