• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.581-584
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• 2008

The catalyst carriers of the mesoporous layer compounds were prepared to carry out the partial oxidation of methane(POM) to hydrogen. The catalytic activities of POM to hydrogen were investigated over Ru(3)/SPK and Ru(3)/SPM catalyst in a fixed bed flow reactor under atmosphere. In addition, the catalysts and carriers were characterized by BET, TEM, TPR. The BET surface areas of the silica-pillared $H^+-kenyaite$(SPK) and the silica-pillared $H^+-magadite$(SPM) were $760m^2/g$ and $810m^2/g$, repectively, and the average pore sizes were 3.0 nm and 2.6 nm, repectively. The nitrogen adsorption isotherms were type IV with developed hysteresis. The TEM showed that the mesoporous layer compounds were formed well. The Ru(3)/SPK and the Ru(3)/SPM catalyst were obtained high hydrogen yields(90%, 87%), and were kept constant high hydrogen yields even about 60 hours at 973 K, $CH_4/O_2=2$, $1.25{\times}10^{-5}g-Cat.hr/ml$. The TPR peaks of Ru(3)/SPK and the Ru(3)/SPM catalyst showed the similar reducibilities around 453 K and 413 K. It could be suggested that SPK and SPM had the physicochemical properties as oxidation catalyst carries from these analysis data.

• Journal of the Korean Ceramic Society
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• v.34 no.3
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• pp.233-240
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• 1997

The Ru-based thick film resistor(TFR) for sintering at 90$0^{\circ}C$ was synthesized to prepare the LCR net-work. These compositions of pyrochlore could be prepared by decreasing the amount of PbO and increasing alumina and silica contents of glass frit. In this study, the sheet resistances of the TFTs. which sint-ered at 90$0^{\circ}C$ after printing on alumina substrate, the sheet resistances of the TFRs on inductor and capa-citor substrate and the interphase between TFR and substrate were observed. And the changes of the sheet resistance were obtained with the contents of RuO2. In case of the TFR sintered at 90$0^{\circ}C$, the sheet resis-tances on alumina substrates were in the range of 103~106$\Omega$/$\square$, but the sheet resistances of TFR on in-ductor and capacitor substrate were not obtained.

• Polymer(Korea)
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• v.35 no.1
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• pp.35-39
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• 2011

In this work, mesoporous carbons (CMK-3) were prepared by a conventional templating method using mesoporous silica (SBA-15) for using catalyst supports in polymer electrolyte membrane fuel cells (PEMFCs). The CMK-3 were chemically activated to obtain high surface area and small pore diameter with different potassium hydroxide (KOH) amounts, i.e., 0, 1, 3, and 4 g as an activating agent. And then Pt-Ru was deposited onto activated CMK-3 (K-CMK-3) by a chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto K-CMK-3 were determined by surface area and pore size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and inductive coupled plasma-mass spectrometry (ICP-MS). The electrochemical properties of Pt-Ru/K-CMK-3 catalysts were also analyzed by cyclic voltammetry (CV). From the results, the K3g-CMK-3 carbon supports activated with 3 g KOH showed the highest specific surface areas. In addition, the K3g-CMK-3 led to uniform dispersion of Pt-Ru onto K-CMK-3, resulted in the enhancement of elelctro-catalystic activity of Pt-Ru catalysts.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.167-172
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• 2011

In this work, the effect of surface treatment on mesoporous carbons (MCs) supports was investigated by analyzing surface functional groups. MCs were prepared by a conventional templating method using mesoporous silica (SBA-15) for using catalyst supports in direct methanol fuel cells (DMFCs). The MCs were treated with different phosphoric acid ($H_3PO_4$) concentrations i.e., 0, 1, 3, 4, and 5 M at 343 K for 6 h. And then Pt-Ru was deposited onto surface treated MCs (H-MCs) by chemical reduction method. The characteristics of Pt-Ru catalysts deposited onto H-MCs were determined by specific surface area and pore size analyzer, X-ray diffraction, X-ray photoelectron, transmission electron microscopy, and inductive coupled plasma-mass spectrometer. The electrochemical properties of Pt-Ru/H-MCs catalysts were also analyzed by cyclic voltammetry experiments. From the results of surface analysis, an oxygen functional group was introduced to the surface of carbon supports. From the results, the H4M-MCs carbon supports surface treated with 4 M $H_3PO_4$ led to uniform dispersion of Pt-Ru onto H4M-MCs, resulting in enhancing the electro-catalytic activity of Pt-Ru catalysts.

• Bulletin of the Korean Chemical Society
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• v.9 no.3
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• pp.137-143
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• 1988

We have investigated the infrared spectra for carbon monoxide chemisorbed on silica supported ruthenium with and without potassium coating within the frequency range of 1800-2200 $cm^{-1}$ at various ruthenium concentrations and CO pressures. For the system without potassium coating, three bands were observed in the infrared spectra when CO was adsorbed on both the reduced and oxidized form of supported ruthenium. However, the relative intensities of these three bands were found to have no interdependence. Therefore, we have assigned each of these bands as arising from the CO stretching vibration for carbon monoxide molecules adsorbed on the Ru sites of different nature. On coating with potassium, the 2030 $cm^{-1}$ band observed for the system without potassium coating was found to suffer red shift by 10-30 $cm^{-1}$ and we conclude that this bathochromic shift is caused by enhancement in the capability of back donation of electrons from the metal atom to the antibonding ${\pi}{\ast}$ orbitals of CO due to the presence of potassium.

• Journal of the Korean Applied Science and Technology
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• v.21 no.4
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• pp.345-351
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• 2004

Highly ordered pure-silica MCM-41 materials possessing well-defined morphology have been successfully prepared with surfactant used as a template. The fabrication of mesoporous silica has received considerable attention due to the need to develop more efficient materials' for catalysis, separations, and chemical sensing. The surface modified MCM-41 was used as anadsorbent for biomolecules. Silica-supported organic groups and DNA adsorption on surface modified MCM-41 were investigated by FT-IR and UV-Vis spectrometer, respectively. The use of MCM-41 as the modification of electrode surfaces were investigated electrochemical properties of metal mediators with biomolecules. The modified ITO electrodes increased peak currents for a redox process of $[Ru(bpy)_3]^{2+}$ relative to the bare electrode. The electrochemical detection of DNA by cyclic voltammetry when the current is saturated in the presence of the mediator appeared more sensitive due to a higher catalytic current on the MCM-41 supported electrodes modified by carboxylic acid functional groups. The carboxyl or amine groups on the surface of MCM-41 interact and react with the $-NH_2$ groups of guanine and backbone, respectively. Highly ordered mesoporous materials with organic groups could find applications as DNA sensors.

• Food Science and Preservation
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• v.19 no.2
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• pp.229-234
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• 2012

The antioxidant substance in black onion was identified. The assays that used 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazo line-6-sulphonic acid) ($ABTS^+$) radicals showed that the ethyl acetate fraction of black onion methanol extract had a higher level of radical-scavenging activity than the other fractions. Two antioxidative compounds were purified and isolated from the ethyl acetate fraction via column chromatographies of silica gel and Sephadex LH-20 using the guided DPPH radical-scavenging assay. The isolated compounds were identified as 3,4-dihydroxybenzoic acid (1) and quercetin (2) based on mass spectrometry and nuclear magnetic resonance. The isolated compounds showed a high level of DPPH and ABTS+ radical-scavenging activity. Compound 2 had a higher level of radical-scavenging activity than 1.

• Journal of Ginseng Research
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• v.43 no.3
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• pp.377-384
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• 2019

Background: Inflammation is widespread in the clinical pathology and closely associated to the progress of many diseases. Triterpenoid saponins as a key group of active ingredients in Panax notoginseng (Burk.) F.H. Chen were demonstrated to show antiinflammatory effects. However, the chemical structures of saponins in the leaves and stems of Panax notoginseng (PNLS) are still not fully clear. Herein, the isolation, purification and further evaluation of the antiinflammatory activity of dammarane-type triterpenoid saponins from PNLS were conducted. Methods: Silica gel and reversed-phase C8 column chromatography were used. Furthermore, preparative HPLC was used as a final purification technique to obtain minor saponins with high purities. MS, NMR experiments, and chemical methods were used in the structural identifications. The antiinflammatory activities of the isolated saponins were assessed by measuring the nitric oxide production in RAW 264.7 cells stimulated by lipopolysaccharides. Real-time reverse transcription polymerase chain reaction was used to measure the gene expressions of inflammation-related gene. Results: Eight new minor dammarane-type triterpene oligoglycosides, namely notoginsenosides LK1-LK8 (1-8) were obtained from PNLS, along with seven known ones. Among the isolated saponins, gypenoside IX significantly suppressed the nitric oxide production and inflammatory cytokines including tumor necrosis $factor-{\alpha}$, interleukin 10, interferon-inducible protein 10 and $interleukin-1{\beta}$. Conclusion: The eight saponins may enrich and expand the chemical library of saponins in Panax genus. Moreover, it is reported for the first time that gypenoside IX showed moderate antiinflammatory activity.