• Title, Summary, Keyword: CMK-3

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Fabrication of CNT/CMK3 Carbon Composites with High Electrical/Thermal Conductive Properties

  • Choi, Seung Dae;Lee, Ju Hyun;Park, Da Min;Kim, Geon-Joong
    • Bulletin of the Korean Chemical Society
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    • v.34 no.7
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    • pp.2155-2161
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    • 2013
  • Composite materials of mesoporous carbon and carbon nanotubes were synthesized using Ni, Co and Pd-loaded CMK3 via a catalytic reaction of methane and $CO_2$. The CNTs grew from the pores of the mesoporous carbon supports, and they were attached tightly to the CMK3 surface in a densely tangled shape. The CNT/CMK3 composite showed both non-graphitic mesoporous structures, and graphitic characteristics originating from the MWCNTS grown in the pores of CMK3. The electrochemical properties of the materials were characterized by their electrorheological effects and cyclic voltammetry. The CNTs/CMK3 composites showed high electrical conductivity and current density. The CNT/CMK3 or KOH-modified CNT/CMK3 particles were incorporated in a PMMA matrix to improve the thermal and electrical conductivity. Even higher thermal conductivity was achieved by the addition of KOH-modified CNT/CMK3 particles.

Influence of Activation of Mesoporous Carbon on Electrochemical Behaviors of Pt-Ru Nanoparticle Catalysts for PEMFCs (고분자 전해질 연료전지 백금-루테늄 나노입자 촉매의 전기화학적 거동에 대한 중형기공 탄소 지지체의 활성화 효과)

  • Kim, Byung-Ju;Park, Soo-Jin
    • 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.

Thermal Insulation Properties of Epoxy/Mesoporous Carbon Composites

  • Heo, Gun-Young;Seo, Min-Kang;Oh, Sang-Yeob;Choi, Kyeong-Eun;Park, Soo-Jin
    • Carbon letters
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    • v.12 no.1
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    • pp.53-56
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    • 2011
  • This study aimed to investigate the influence of mesoporous carbons on the thermal insulation properties of epoxy/mesoporous carbon composites. The mesoporous carbon (CMK-3) was prepared by conventional templating method using SBA-15. The epoxy/mesoporous carbon composites were prepared by mixing the synthesized CMK-3 with diglycidylether of bisphenol A (DGEBA). As experimental results, the curing reactivities of the DGEBA/CMK-3 composites were found to decrease with the addition of the CMK-3. Also, the thermal conductivities of DGEBA/CMK-3 composites were found to decrease with increasing CMK-3 content. This could be interpreted in terms of the slow thermal diffusion rate resulting in pore volume existing in the gaps in the interfaces between the mesoporous carbon and the DGEBA matrix.

Hydrogen Storage Using Pd Doped Mesoporous Carbon Materials (팔라듐이 담지된 중형 기공성 탄소 재료를 이용한 수소 저장)

  • Kim, Wooyoung;Kim, Dongmin;Hong, Youngteak;Kang, Taegyun;Yi, Jongheop
    • Clean Technology
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    • v.12 no.2
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    • pp.107-111
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    • 2006
  • Two types of mesoporous carbons, CMK-3 and CMK-5, were prepared using mesoporous silica as a removable template, and their hydrogen storage capacities were evaluated. For the purpose of comparison, MWCNT (multi-walled carbon nanotubes) was selected and the adsorption of hydrogen was measured. The amount of hydrogen adsorbed on carbon materials was found to be closely related to the surface areas of carbon samples: The higher the surface area of the carbon material, the larger amount of hydrogen was adsorbed. The hydrogen storage capacity increased in the order of CMK-5 > CMK-3 > MWCNT. In addition, hydrogen storage capacity was greatly enhanced by the Pd-doping onto CMK-5. When the metallic Pd was doped on the carbon material, the adsorption amount of hydrogen via a hydrogen spill-over mechanism was crucial to the hydrogen storage capacity of Pd-doped CMK-5.

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Quality Characteristics of Baechu Kimchi at Jangsu Area as Compared with Commercial Kimchi (장수지역 배추김치와 시판 배추김치의 품질 평가)

  • Lee, Young-Sook;Cha, Jin-A;Rho, Jeong-Ok
    • Journal of the East Asian Society of Dietary Life
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    • v.23 no.4
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    • pp.413-422
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    • 2013
  • This study investigates the kimchi from Jangsu area (JSK) and its comparison with commercial kimchi (CMK). We conducted a sensory evaluation for the pH, titratable acidity, salinity, hunter's color values and mechanical characteristics of kimchi. The pH of JSK is significantly higher than CMK throughout the fermentation (p<0.001). At 15 days, JSK reached the stage of optimal maturity for pH 4.23~4.55 and CMK showed pH 3.96~4.00 as conditions after the optimal maturity (p<0.001). From the results of acidity analyses, CMK also showed higher acidity values than JSK (p<0.001), indicating that the rate of fermentation progress was faster in CMK. Salinity of JSK was a litter higher than CMK1 and CMK2 (p<0.001) and JSK indicated significantly higher L, a, b values during fermentation (p<0.001). Moreover, the textural values were significantly higher in JSK2 and JSK3 retaining hardness of the tissues. In the sensory assessment, the color, flavor, crispness, taste, and overall preferences were higher in JSK3 at 15 days and 30 days than CMK. Therefore, it seems necessary for recipe developments of kimchi with local characteristics in order to industrialize kimchi by using alpine crops at Jangsu area.

Application of Porous Carbon Catalyst Activating Reaction of Positive Electrode in Vanadium Redox Flow Battery (바나듐 레독스 흐름전지의 양극반응 활성화를 위한 다공성 탄소 촉매의 적용)

  • Jeong, Sanghyun;Chun, Seung-Kyu;Lee, Jinwoo;Kwon, Yongchai
    • Journal of Energy Engineering
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    • v.23 no.3
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    • pp.150-156
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    • 2014
  • In this study, we implemented a research for improving performance of redox flow battery (RFB) via enhancing reaction rate of vanadium reaction ($[VO]^{2+}/[VO_2]^+$) that was a rate determining step. For doing that, porous catalyst, CMK3 was employed and its perfoamance was compared with that of Vulcan(XC-72) and commercial Pt/C (Johnson-Matthey Pt 20wt.%). Cyclic voltammetry (CV) was used for inspecting reactivity, while its structural feature was measured by TEM and BET&BJH. Also, Charge-discharge trend was evaluated by single cell tests. As result, CMK3 showed 6 times better catalytic activity and twice better reversibility than Vulcan(XC-72), while it showed larger surface area than Vulcan XR due to its porous structure. Furthermore, CMK3 indicated 85% of reactivity and reversibility of commercial Pt/C despite its Pt-less situation. In single cell tests, when RFB adopted CMK3 as catalyst for positive electrode, its charge-discharge curve result was better than that adopted commercial Pt/C.

Influence of Magnesium Oxide on Carbon Dioxide Adsorption Behaviors of Mesoporous Carbons (메조포어러스카본의 마그네슘 옥사이드의 처리에 따른 이산화탄소 흡착 거동)

  • Jang, Dong-Il;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • pp.221.2-221.2
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    • 2011
  • In this study, we prepared the magnesium oxide decorated ordered mesoporous carbons processed by the reduction of magnesium oxide precursor on the CMK-3 surfaces in order to investigate the characterization and the effect on their carbon dioxide adsorption behaviors. The magnesium contents of the prepared samples were characterized using XPS. The textural properties of the prepared samples were investigated by $N_2$/77 K adsorption isotherms by BET equation. The carbon dioxide adsorption capacities of the prepared samples were investigated by the amounts of carbon dioxide adsorptions at 298 K and 1.0 atm. The results showed that the magnesium oxide on the CMK-3 surface enhanced interaction between carbon dioxide and adsorbents. Consequently, it was found that the magnesium oxide led to an increase in the carbon dioxide adsorption capacity of the CMK-3.

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Adsorption of Phenol on Mesoporous Carbon CMK-3: Effect of Textural Properties

  • Haque, Enamul;Khan, Nazmul Abedin;Talapaneni, Siddulu Naidu;Vinu, Ajayan;JeGal, Jong-Geon;Jhung, Sung-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.31 no.6
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    • pp.1638-1642
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    • 2010
  • Mesoporous carbon CMK-3s with different textural properties have been used for the adsorption of phenol to understand the necessary physicochemical properties of carbon for the efficient removal of phenol from contaminated water. The kinetic constants (both pseudo-second order and pseudo-first-order kinetics) increase with increasing pore size of carbons. The maximum adsorption capacities correlate well with micropore volume compared with surface area or total pore volume even though large pore (meso or macropore) may contribute partly to the adsorption. The pore occupancies also explain the importance of micropore for the phenol adsorption. For efficient removal of phenol, carbon adsorbents should have large micropore volume and wide pore size for high uptake and rapid adsorption, respectively.

Preparation of Mesoporous SiCBN Ceramic Templated by Mesoporous Carbon

  • Nghiem, Quoc Dat;Ryoo, Hyang-Im;Kim, Dong-Pyo
    • Journal of the Korean Ceramic Society
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    • v.44 no.7
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    • pp.358-361
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    • 2007
  • Well-ordered mesoporous SiCBN ceramics have been successfully synthesized by infiltrating a polymeric precursor, which was prepared from borazine and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane via a hydroboration reaction, into a mesoporous carbon (CMK-3) as a hard template. This was followed by pyrolysis at $1400^{\circ}C$ under nitrogen gas and subsequent oxidative removal of the carbon template without chemical etching. The prepared mesoporous SiCBN ceramic was characterized by a small-angle XRD, TEM, and BET surface area. The resulting mesoporous SiCBN ceramic revealed a BET surface area of $275 m^2g^{-1}$ and a pore volume of $0.8 cm^3 g$ with no crystallization.

Synthesis of Mesoporous TS-1 for Catalytic Oxidative Desulfurization

  • Park, Chul-Woo;Kim, Tae-Kyung;Ahn, Wha-Seung
    • Bulletin of the Korean Chemical Society
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    • v.30 no.8
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    • pp.1778-1782
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    • 2009
  • Mesoporous TS-1 catalysts were prepared via a nanocasting route using two different carbon template sources of CMK-3 and commercial carbon black. Products were characterized by XRD, UV-Vis spectroscopy, SEM, TEM, and $N_2$ adsorption- desorption measurement. The catalytic performances of the samples for allylchloride epoxidation and oxidative desulfurization of the representative refractory sulfur compounds, dibenzothiophene and 4,6-dimethyldibenzothiophene, were compared against those of conventional TS-1. Whilst the allychloride epoxidation activity for the mesoporus TS-1 samples were similar, mesoporous TS-1 exhibited significantly higher catalytic activities than conventional TS-1 in oxidative desulfurization.