• Title/Summary/Keyword: Ni Catalyst

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Cation Exchanged Silicate Catalyst for Ethylene Polymerization (에틸렌 중합을 위한 陽이온이 交換된 규산염 觸媒)

  • Jong Rack Sohn;Hyen Bae Park
    • Journal of the Korean Chemical Society
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    • v.26 no.5
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    • pp.282-290
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    • 1982
  • Several cation exchanged-layer silicate catalysts were prepared from acid clay mainly consisted of montmorillonite, and their catalytic activities for the ethylene polymerization were studied at room temperature. It was found that overNi2+ -Mont, dimerization of ethylene to n-butene proceeded selectively.Ni2+ -Mont was activated by evacuation at elevated temperature, giving a maximum temperature, 150C . The variations in catalytic activities were closely correlated to the acidity of the catalysts.Cr3+ -Mont exhibited a high activity for the polymerization, showing, a maximum at the evacuation temperature of 450C. The active site in Cr3+-Mont was considered to be Cr3+ ion.

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Fabrication of a nano-sized conical-type tungsten field-emitter based on carbon nanotubes (탄소나노튜브를 이용한 텅스텐 나노팁 전계방출기 제작)

  • Park, Chang-Kyun;Kim, Jong-Pil;Kim, Young-Kwang;Park, Jin-Seok
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1220-1221
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    • 2008
  • Submicron-sized conical-type tungsten(W) field-emitters based on carbon nanotubes(CNTs) are fabricated with the configuration of CNTs/catalyst(Ni)/buffer(Al/Ni/TiN)/W-tip. This study focuses on elucidating how the Al/Ni/TiN stacked buffer layer affects the structural properties of CNTs and the electron-emission characteristics of CNT-emitters. Field-emission scanning electron microscopy(FESEM), high-resolution transmission electron microscopy(HRTEM), and x-ray photoelectron spectroscopy(XPS) are used to monitor the nanostructures, surface morphologies, chemical bonds of all the catalysts and CNTs grown. The crystalline structure of CNTs is also characterized by Raman spectroscopy. Furthermore, the measurement of field-emission characteristics for the field-emitters fabricated shows that the emitter using the Al/Ni/TiN stacked buffer reveals the excellent performances.

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Fabrication of MISFET type hydrogen sensor for high Performance (고성능 MISFET형 수소센서의 제작과 특성)

  • Kang, K.H.;Park, K.Y.;Han, S.D.;Choi, S.Y.
    • Journal of Hydrogen and New Energy
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    • v.15 no.4
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    • pp.317-323
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    • 2004
  • We fabricated a MISFET using Pd/NiCr gate for the detecting of hydrogen gas in the air and investigated its electrical characteristics. To improve stability and high concenntration sensitivity and remove the blister generated by the penetration of hydrogen atoms Pd/NiCr catalyst gate metal are used as dual gate. To reduce the gate drift voltage caused by the inflow of hydrogen, the gate insulators of sensing and reference FFET were constructed with double insulation layers of silicon dioxide and silicon nitride. The hydrogen response of MISFET were amplified with the difference of gate voltages of both MISFET. To minimize the drift and the noise, we used a OP177 operational amplifier. The sensitivity of the Pd/NiCr gate MISFET was lower than that of Pd/Pt gate MISFET, but it showed good stability and ability to detect high concentration hydrogen up to 1000ppm.

Growth of Vertically Aligned Carbon Nanotubes on Co-Ni Alloy Metal (Co-Ni 합금위에서 수직방향으로 정렬된 탄소나노튜브의 성장)

  • Ryu, Jae-Eun;Lee, Cheol-Jin;Lee, Tae-Jae;Son, Gyeong-Hui;Sin, Dong-Hyeok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.8
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    • pp.451-454
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    • 2000
  • We have grown vertically aligned carbon nanotubes in a large area of Co-Ni codeposited Si substrates by the thermal CVD usign C2H2 gas. Since the discovery of carbon nanotubes, growth of carbon nanotubes has been achieved by several methods such as laser vaporization, arc discharge, and pyrolysis. In particular, growth of vertically aligned nanotubes is important to flat panel display applications. Recently, vertically aligned carbon nanotubes have been grown on glass by PECVD. Aligned carbon nanotubes can be also grown on mesoporous silica and Fe patterned porous silicon using CVD. In this paper, we demonstrate that carbon nanotubes can be vertically aligned on catalyzed Si substrate when the domain density of catalytic particles reaches a certain value. We suggest that steric hindrance between nanotubes at an initial stage of the growth forces nanotubes to align vertically and each nonotubes are grown in bundle.

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Solar CO2 Reforming of Methane Using Ni/γAl2O3/Metallic foam device (Ni/γAl2O3/Metallic device를 이용한 고온 태양열 메탄-이산화탄소 개질반응)

  • Shin, Il-Yoong;Lee, Ju-Han;Lee, Jin-Gyu;Seo, Tae-Beom
    • 한국태양에너지학회:학술대회논문집
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    • 2011.04a
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    • pp.275-281
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    • 2011
  • Solar reforming of methane with CO2 was successfully tested with a direct irradiated absorber on a parabolic dish capable of 5kWth solar power. The new type of catalytically activated metallic foam absorber was prepared, and its activity was tested. Ni was applied as the active metal on the gamma - alumina coated Ni metal foam for the preparation of the catalytically-activated metal foam layer. Compared to conventional direct irradiation of the catalytically-activated ceramic foam absorber, this new metallic foam absorber is found to exhibit a superior reaction performance at the relatively low insolation or at low temperatures. In addition, unlike direct irradiation of the catalytically-activated ceramic foam absorber, metallic foam absorber has better thermal resistance, which prevents the emergence of cracks caused by mechanical or thermal shock. The total solar power absorbed reached up to 2.1kW and the maximum CH4 conversion was almost 40%.

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Thermal Decomposition of PVB(polyvinyl butyral) and Ni Green Sheet (PVB와 니켈 그린 시트의 열분해)

  • Seo, Jung Ju;Kuk, Seung Taek;Kim, Keon
    • Journal of the Korean Chemical Society
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    • v.40 no.3
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    • pp.180-186
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    • 1996
  • To determine burn-out condition of polyvinyl butyral as binder, TGA and GC/MS were used to analyze decomposed products of PVB and Ni green sheet during binder pyrolysis. The produced gases are similar in kind each other but the relative amount of produced gases was different. When the atmosphere air contains water, relatively larger amount of carboxylic acids and aromatic compounds were detected, and the amount of the decomposed products were larger in Ni green sheet than PVB alone. And Ni acted as a catalyst in the thermal decomposition of PVB.

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Synthesis of Carbon Nanotube and Optical Application (탄소나노튜브의 제조 및 광학적 응용 연구)

  • Joo, Young-Joon;So, Won-Wook;Kim, Heejoo;Chol, Ho-Suk;Moon, Sang-Jin
    • Journal of Hydrogen and New Energy
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    • v.14 no.3
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    • pp.247-257
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    • 2003
  • To investigate the effect of preparing condition on the physical properties of carbon nanotubes suitable for optical applications, carbon nanotubes were synthesized by thermal chemical vapor deposition using Ni particles as a catalyst on stainless steel substrate and acetylene as a reactant gas. To examine the physical and optical properties, SEM, TEM, Ram an, UV-visible, and photoluminescence spectroscopy were used. The physical properties of carbon nanotubes such as diameter, degree of growth density and morphology were closely related to such experimental conditions as Ni particle size, growing pressure, and etching condit on of Ni particles, it appeared from the light absorbance and photoluminescence spectra of carbon nanotube mixture prepared with an addition of a photopolymer, P3HT(Poly(3-hexylthIop hene)) that carbon nanotube could do a role as a kind of electron acceptor for solar cell application.

Catalytic growth of single wall carbon nanotubes by laser vaporization and its purification and The carbon nanotube growth on the Si substrate by CVD method

  • Lee, Sung won;Jung in Sohn;Lee, Seonghoon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2000.02a
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    • pp.213-213
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    • 2000
  • Direct laser vaporization of transition-metal(Co, Ni)/graphite composite pellet produced single wall carbon naotubes(SWNT) in the condensing vapor in a heated flow cylinder-type tube furnace, Transition metal/graphite composite pellet target was made by mixing graphite, Co, and Ni in 98:1:1 atomic weight ratios, pressing the mixed powder, and curing it. The target was placed in a tube furnace maintained at 1200C and Ar inert collision gas continuously flowed into the tube. The 2nd harmonic, 532nm wavelength light from Nd-YAG laser was used to vaporize the tube. The carbon nanotubes produced by the laser vaporization were accumulated on quartz tube wall. The raw carbon nanotube materials were purified with surfactants(Triton X-100) in a ultrasonicator. These carbon nanotubes were analyzed using SEM, XRD, and Raman spectroscopic method. The carbon nanotube growth on the Ni-patterned Si substrate was investigated by the CVD process. Transition-metal, Ni and CH4 gas were used as a catalyst and a reactant gas, respectively. The structure and the phonon frequencies of the carbon nanotubes formed on the patterned Si substrate were measured by SEM and Raman spectrometer.

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A Study on the Characteristics of Ni/Ce0.9Gd0.1O2-x and Cu/Ce0.9Gd0.1O2-x Catalysts for Methanol Steam Reforming Synthesized by Solution Combustion Process (용액연소법으로 합성한 Ni/Ce0.9Gd0.1O2-x와 Cu/Ce0.9Gd0.1O2-x 촉매의 메탄올 수증기 개질 특성 연구)

  • LEE, JUNGHUN
    • Journal of Hydrogen and New Energy
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    • v.30 no.3
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    • pp.209-219
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    • 2019
  • Methanol is a liquid fuel which could also be produced from renewable energy sources and has appreciably high energy density. In this work, we investigated the application of Ce0.9Gd0.1O2x supported Cu and Ni catalysts for hydrogen production via methanol steam reforming. Catalysts were synthesized by solution combustion synthesis. The prepared catalysts with various active materials and Cu loading amounts were tested in a reactor at 200300C, 0-5 barg range and steam to methanol molar ratio was 1.5. The catalytic properties of Cu and Ni were compared, and the catalytic performance was shown to depend on the amounts of metal loading and operating conditions such as reaction temperature and pressure.

A Study on Catalytic Pyrolysis of Polypropylene with Ni/sand (Ni/sand를 이용한 폴리프로필렌 촉매 열분해 연구)

  • Kim, Soo Hyun;Lee, Roosse;Sohn, Jung Min
    • Clean Technology
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    • v.27 no.3
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    • pp.232-239
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    • 2021
  • In order to develop a novel system named "thermal medium and gas circulation type pyrolysis system," this study was conducted to obtain basic data for process simulation before performing the pyrolysis experiment. Polypropylene (PP) was chosen as model material in the basic pyrolysis experiment instead of waste plastic and fluidized sand (hereinafter referred to as "sand"), and it was used as a heat transfer material in the "thermal medium and gas circulation type pyrolysis system." Ni was impregnated as an active catalyst on the sand to promote catalytic pyrolysis. The basic physical properties of PP were analyzed using a thermogravimetric analyzer, and pyrolysis was performed at 600 ℃ in an N2 atmosphere to produce liquid oil. The distribution of the carbon number of the liquid oil generated through the catalytic pyrolysis reaction was analyzed using GC/MS. We investigated the effects of varying the pyrolysis space velocity and catalyst amount on the yield of liquid oil and the carbon number distribution of the liquid oil. Using Ni/sand, the yield of liquid oil was increased except with the pyrolysis condition of 10 wt% Ni/sand at a space velocity of 30,000 h-1, and the composition of C6 ~ C12 hydrocarbons increased. With increases in the space velocity, higher yields of liquid oil were obtained, but the composition of C6 ~ C12 hydrocarbons was reduced. With 1 wt% Ni/sand, the oil yield obtained was greater than that obtained with 10 wt% Ni/sand. In summary, when 1 wt% Ni/sand was used at a space velocity of 10,000 h-1, the oil yield was 60.99 wt% and the composition of C6 ~ C12 hydrocarbons was highest at 42.06 area%.