• Title/Summary/Keyword: Ni Catalyst

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Production of H2H2 Gas in Pyrolysis of Paper Biomass using Ni-based Catalysts (종이 바이오매스의 열분해에서 니켈 촉매에 의한 수소제조특성)

  • Choi, Yong-Keun;Chattopadhyay, Jeeta;Kim, Chul-Ho;Kim, Lae-Hyun;Son, Jae-Ek;Park, Dea-Won
    • Journal of Hydrogen and New Energy
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    • v.19 no.6
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    • pp.514-519
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    • 2008
  • In the present study, biomass pyrolysis was done using five different kinds of catalysts with change in the support species and their compositions. Ni was loaded on alumina, ceria and alumina-ceria supports using co-precipitation method. In all the catalysts, 30wt% of nickel was loaded on the support materials. The paper used in daily writing purposes was taken into account as biomass sample. In the experiment, 19 of biomass was mixed with o.1g of each catalyst separately. Thermogravimetric analysis (TGA) was performed with all the catalysts diminished the initial degradation temperature of paper biomass sample considerably. During the pyrolysis process, the temperature was raised from room temperature to 800C800C with the heating rate of 10C10C/min in the furnace. The cumulative H2H2 volume had reached the best value of l4.02ml with the Ni/Al2O3CeO2Al2O3CeO2 30wt%/(50wt%-50wt%) catalysts. In presence of all the catalysts, the highest amount of H2H2 was produced at 800C800C, 10min. of residence time.

Facile Synthesis of M-MOF-74 (M=Co, Ni, Zn) and its Application as an ElectroCatalyst for Electrochemical CO2 Conversion and H2 Production

  • Choi, Insoo;Jung, Yoo Eil;Yoo, Sung Jong;Kim, Jin Young;Kim, Hyoung-Juhn;Lee, Chang Yeon;Jang, Jong Hyun
    • Journal of Electrochemical Science and Technology
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    • v.8 no.1
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    • pp.61-68
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    • 2017
  • Electrochemical conversion of CO2CO2 and production of H2H2 were attempted on a three-dimensionally ordered, porous metal organic framework (MOF-74) in which transition metals (Co, Ni, and Zn) were impregnated. A lab-scale proton exchange membrane-based electrolyzer was fabricated and used for the reduction of CO2CO2. Real-time gas chromatography enabled the instantaneous measurement of the amount of carbon monoxide and hydrogen produced. Comprehensive calculations, based on electrochemical measurements and gaseous product analysis, presented a time-dependent selectivity of the produced gases. M-MOF-74 samples with different central metals were successfully obtained because of the simple synthetic process. It was revealed that Co- and Ni-MOF-74 selectively produce hydrogen gas, while Zn-MOF-74 successfully generates a mixture of carbon monoxide and hydrogen. The results indicated that M-MOF-74 can be used as an electrocatalyst to selectively convert CO2CO2 into useful chemicals.

Direct synthesis mechanism of amorphous SiOxSiOx nanowires from Ni/Si substrate (Ni/Si 기판을 사용하여 성장시킨 비결정질 SiOxSiOx 나노 와이어의 성장 메커니즘)

  • Song, W.Y.;Shin, T.I.;Lee, H.J.;Kim, H.;Kim, S.W.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.6
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    • pp.256-259
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    • 2006
  • The amorphous SiOxSiOx nanowires were synthesized by the vapor phase epitaxy (VPE) method. SiOxSiOx nanowires were formed on silicon wafer of temperatures ranged from 8001100C8001100C and nickel thin film was used as a catalyst for the growth of nanowires. A vapor-liquid-solid (VLS) mechanism is responsible for the catalyst-assisted amorphous SiOxSiOx nanowires synthesis in this experiment. The SEM images showed cotton-like nanostructure of free standing SiOxSiOx nanowires with the length of more than about 10μm10μm. The SiOxSiOx nanowires were confirmed amorphous structure by TEM analysis and EDX spectrum reveals that the nanowires consist of Si and O.

A Study on the CO2 Methanation in Power to Gas (P2G) over Ni-Catalysts (Ni 촉매 상에서 Power to Gas (P2G) 기술의 CO2 메탄화 반응에 관한 연구)

  • YEOM, GYUIN;SEO, MYUNGWON;BAEK, YOUNGSOON
    • Journal of Hydrogen and New Energy
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    • v.30 no.1
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    • pp.14-20
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    • 2019
  • The power to gas (P2G) is one of the energy storage technologies that can increase the storage period and storage capacity compared to the existing battery type. One of P2G technologies produces hydrogen by decomposing water from renewable energy (electricity) and the other produces CH4CH4 by reacting hydrogen with CO2CO2. The objective of this study is the reaction of CO2CO2 methanation which synthesized methane by reacting carbon dioxide and hydrogen. The effect of CO2CO2 conversion and CH4CH4 selectivity on reaction temperature, pressure, and methane contents over 40% Ni catalyst was mainly investigated throughout this study. As a result, the activity of this catalyst appeared to be the highest in CH4CH4 yield at around 400C400C and the selectivity of CH4CH4 increased with increasing reaction pressure. The methane content was not significantly influenced below 3% of all componets. As the space velocity increases from 10,000 to 30,000/hr, the CO2CO2 conversion rate tends to decrease.

Hydrotreating for Stabilization of Bio-oil Mixture over Ni-based Bimetallic Catalysts (Ni계 이원금속 촉매에 의한 혼합 바이오오일의 안정화를 위한 수소첨가 반응)

  • Lee, Seong Chan;Zuo, Hao;Woo, Hee Chul
    • Clean Technology
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    • v.27 no.1
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    • pp.69-78
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    • 2021
  • Vegetable oils, such as palm oil and cashew nut shell liquid (CNSL), are used as major raw materials for bio-diesel in transportation and bio-heavy oil in power generation in South Korea. However, due to the high unsaturation degree caused by hydrocarbon double bonds and a high content of oxygen originating from the presence of carboxylic acid, the range of applications as fuel oil is limited. In this study, hydrotreating to saturate unsaturated hydrocarbons and remove oxygen in mixed bio-oil containing 1/1 v/v% palm oil and CNSL on monometallic catalysts (Ni and Cu) and bimetallic catalysts (Ni-Zn, Ni-Fe, Ni-Cu Ni-Co, Ni-Pd, and Ni-Pt) was perform under mild conditions (T = 250 ~ 400 ℃, P = 5 ~ 80 bar and LHSV = 1 h-1). The addition of noble metals and transition metals to Ni showed synergistic effects to improve both hydrogenation (HYD) and hydrodeoxygenation (HDO) activities. The most promising catalyst was Ni-Cu/��-Al2O3, and in the wide range of the Ni/Cu atomic ratio of 9/1~1/4, the conversion for HYD and HDO reactions of the catalysts were 90-93% and 95-99%, respectively. The tendency to exhibit almost constant reaction activity in these catalysts of different Ni/Cu atomic ratios implies a typical structure-insensitive reaction. The refined bio-oil produced by hydrotreating (HDY and HDO) had significantly lower iodine value, acid value, and kinetic viscosity than the raw bio-oil and the higher heating value (HHV) was increased by about 10%.

[ CH4CH4 ] steam reforming over Ni-Ru bimetallic catalysts (Ni-Ru 계열 촉매 상에서의 CH4CH4 수증기 개질 반응)

  • Jeong Jin Hyeok;Lee Jung Won;Lee Duek Ki;Kim Dong Hyun;Seo Dong Joo;Seo Yutek;Yoon Wang Lei
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.256-259
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    • 2005
  • 본 연구에서는 기존 니켈 활성성분만의 알루미나담지 촉매에 비해 고온에서의 수소를 사용한 환원 전처리 과정을 거치지 않고도 높은 반응활성을 나타내며, 반응 중 탄소침적에 대한 촉매 저항성에서도 우수한 결과를 나타낸 루테늄-니켈 촉매에 대해보고 하고자 한다. 메탄 수증기 개질 반응을 통해, 루테늄을 최종적으로 담지한 알루미나 담지니켈계 촉매는 별도의 전처리과정 없이 650C650C에서부터 높은 반응성을 보였으며, 루테늄과 니켈을 동시에 담지한 경우보다 더 우수한 활성을 나타내었다. Ru의 담지량을 달리한 실험에서는RU(0.5)/Ni(20)/Al2O3RU(0.5)/Ni(20)/Al2O3 촉매가 가장 높은 활성을 보였다. H2TPRH2TPR 분석 결과, Ru(0.5)/Ni(20)/A12O3Ru(0.5)/Ni(20)/A12O3촉매의 경우 세 가지 환원 피크가 나타났으며, Ni(20)/A12O3Ni(20)/A12O3촉매와 비교해 볼 때, 저온(<130C)130C)에서 환원가능한 RUO2RUO2의 존재를 확인할 수 있었다. 담지된 RU은 분산도가 높아, XRD분석 결과에서 Ru이나 RuO2RuO2의 특성 피크가 존재하지 않았다. 또한 650C650C에서 10시간 개질반응 후 얻어진 촉매에 대해 O2TGAO2TGA를 분석한 결과, Ni(20)/Al2O3Ni(20)/Al2O3촉매는 7.2wt%7.2wt% 정도의 큰 무게 감소를 보였으며, 이는 촉매 표면에 생성된 carbon tube에 의한 것임을 SEM 분석을 통해 알 수 있었다 이에 반해, Ru(0.5)/Ni(20)/Al_2O_Ru(0.5)/Ni(20)/Al_2O_ 촉매는 O2TGAO2TGA0.3wt%0.3wt% 정도 무게 증가에 그쳤으며, SEM 분석상 carbon tube의 생성이 크게 억제되었음을 알 수 있었다.

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Ni Nanoparticles-Graphitic Carbon Nanofiber Composites for Pt-Free Counter Electrode in Dye-Sensitized Solar Cells (염료감응 태양전지의 비백금 상대전극을 위한 니켈 나노입자-흑연질 탄소나노섬유 복합체)

  • Oh, Dong-Hyeun;Koo, Bon-Ryul;Lee, Yu-Jin;An, HyeLan;Ahn, Hyo-Jin
    • Korean Journal of Materials Research
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    • v.26 no.11
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    • pp.649-655
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    • 2016
  • Ni nanoparticles (NPs)-graphitic carbon nanofiber (GCNF) composites were fabricated using an electrospinning method. The amounts of Ni precursor used as catalyst for the catalytic graphitization were controlled at 0, 2, 5, and 8 wt% to improve the photovoltaic performances of the nanoparticles and make them suitable for use as counter electrodes for dye-sensitized solar cells (DSSCs). As a result, Ni NPs-GCNF composites that were fabricated with 8 wt% Ni precursors showed a high circuit voltage (0.73 V), high photocurrent density (14.26mA/cm214.26mA/cm2), and superb power-conversion efficiency (6.72%) when compared to those characteristics of other samples. These performance improvements can be attributed to the reduced charge transport resistance that results from the synergetic effect of the superior catalytic activity of Ni NPs and the efficient charge transfer due to the formation of GCNF with high electrical conductivity. Thus, Ni NPs-GCNF composites may be used as promising counter electrodes in DSSCs.

Enhancement of oxygen evolution reaction of NiCo LDH nanocrystals using Mo doping (Mo 도핑을 이용한 NiCo LDH 나노결정의 산소발생반응 향상)

  • Kyoungwon Cho;Jeong Ho Ryu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.34 no.3
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    • pp.92-97
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    • 2024
  • To improve the efficiency of water splitting systems for hydrogen production, the high overvoltages of electrochemical reactions caused by catalysts in the oxygen evolution reaction (OER, Oxygen Evolution Reaction) must be reduced. Among them, LDH (Layered Double Hydroxide) compounds containing transition metal such as Ni, are attracting attention as catalyst materials that can replace precious metals such as platinum that are currently used. In this study, nickel foam, an inexpensive metallic porous material, was used as a support, and NiCo LDH (Layered Double Hydroxide) nanocrystals were synthesized through a hydrothermal synthesis process. In addition, changes in the shape, crystal structure, and water decomposition characteristics of the Mo-doped NiCo LDH nanocrystal samples synthesized by doping Mo to improve OER properties were observed.

Selective Silylation Reaction of Aldehydes with 1,1'-Bis(dimethylsilyl)ferrocene in the Presence of Ni/Pt Catalyst (니켈/백금 촉매에 의한 1,1'-Bis(dimethylsilyl)ferrocene과 Aldehydes의 선택적 Silylation 반응)

  • Kim, Jin-Sik;Choi, Sung-Keun;Lee, Jung-Hyun;Kong, Young-Kun
    • Journal of the Korean Chemical Society
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    • v.51 no.3
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    • pp.232-239
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    • 2007
  • The reaction of 1,1'-bis(dimethylsilyl)ferrocene with various aldehydes in the presence of a catalytic amount of Ni(PEt3)4 lead to the acyclic products by monohydrosilylation. The same reaction in the presence of a catalytic amount of (C2H4)Pt(PPh3)2 leads to the different cyclic six membered ring compound by double silylation. Platinum catalyzed double silylation of 4-cyanobenzaldehyde was generated 5,6-ferrocenylene-1,1,4,4,-tetramethyl-2-oxa-2- cyanophenyl-1,4-disylacyclehexane which was crystallized to have crystal structure.

Leaching Characteristics of Unregulated Heavy Metals in Specified Wastes (지정폐기물 중 미규제 중금속류의 용출 특성)

  • Jeon, Tae-Wan;Shin, Sun-Kyoung;Lee, Jeong-Ah;Kim, Hyoung-Seop
    • Journal of Korean Society of Environmental Engineers
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    • v.30 no.2
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    • pp.213-217
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    • 2008
  • The objective of this research is to investigate the leaching characteristics of unregulated heavy metals such as Ni, Zn, Ba, Be, Sb, Se, V in specified waste. 108 waste samples which were taken from the representative facilities emitting hazardous substances, were analyzed. The rate of leaching of heavy metal was measured using an official test method. From the results, wastewater treatment sludge and dust contained much Ni, and Zn was detected in all samples. Dust and waste catalyst producted from petroleum-refining process tended to reveal V in high concentration. Ba, Be, Sb, Se showed low concentration, but require additional analyses of waste generated at different industries.