• Title/Summary/Keyword: Interlayer spacing

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Characteristics of Exfoliated Graphite Prepared by Intercalation of Gaseous SO3into Graphite

  • Lee, Beom-Jae
    • Bulletin of the Korean Chemical Society
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    • v.23 no.12
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    • pp.1801-1805
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    • 2002
  • The graphite intercalation compounds(GIC) were prepared by a dry process that led to the intercalation from the direct reaction of gaseous $SO_3$ with flake type graphite. The basal spacing of the GIC was increased from 8.3 ${\AA}$ to 12 in the gallery height. The ejection of interlayer $SO_3$ molecules by the heating for 1 minute at $950^{\circ}C$ resulted in an exfoliated graphite (EG) with surprisingly high expansion in the direction of c-axis. The expansion ratios of the exfoliated graphites were increased greatly between 220 times and 400 times compared to the original graphite particles, and the bulk density was range of 0.0053 to 0.01 $g/cm^3$, depending on reaction time. The pore size distribution of exfoliated graphite was in the range of $10-170{\mu}m$, which exhibites both mesoporosity and macroporosities. This result indicates that the direct reaction of graphite paricles with gaseous $SO_3$ can be proposed as an another route for the exfoliated graphite having excellent physical properties.

Preparation of Porous Graphite by Using Template of Co- and Ni-Magadiite (Co, Ni 마가다이트 주형을 이용한 다공성 흑연의 합성)

  • Jeong Soon-Yong
    • Journal of Powder Materials
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    • v.12 no.2 s.49
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    • pp.151-158
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    • 2005
  • Porous graphite was synthesized by removal of template in HF after pyrolysis of pyrolyzed fuel oil (PFO) at $900^{\circ}C$ using the template of Co or Ni intercalated magadiite. Porous graphite had a plate structure like template, and d-spacing value of about 0.7 nm. The extent of crystallization of porous graphite was dependent on the contents of Co or Ni intercalated in interlayer. It can be explained that the metal such as Co and Ni acts as a promotion catalyst for graphite formation. Porous graphite shows the surface area of $328\sim477 m^2/g$.

Fabrication of Graphene Using Exfoliation Method (박리법을 이용한 그래핀 제조)

  • Lee, Jeong-Su;Kim, Bu-Ahn;Moon, Chang-Kwon
    • Journal of Power System Engineering
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    • v.18 no.6
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    • pp.7-12
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    • 2014
  • The effect of various synthesis conditions in the fabrication of graphene using the exfoliation methods has been investigated. Graphite oxide and graphene fabricated by various synthesis conditions were identified by SEM and XRD. Graphite oxide was made from graphite by the chemical oxidation, and graphene was manufactured from graphite oxide by thermal exfoliation method. As a result, it is confirmed that graphite oxide was well formed from graphite, and the graphene could be obtained from graphite oxide. And it was found that the interlayer spacing between the graphene layers depended on the reaction time and particle size, regardless of the reaction temperature from $5^{\circ}C$ to $25^{\circ}C$.

Trimeric Chromium Oxyformate Route to Chromia-Pillared Clay

  • Yun, Ju Byeong;Hwang, Seong Ho;Choe, Jin Ho
    • Bulletin of the Korean Chemical Society
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    • v.21 no.10
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    • pp.1049-1051
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    • 2000
  • A chromia-pillared clay has been prepared by ion exchange type intercalation reaction between the sodium ion in montmorillonite and the trimeric chromium oxyformate (TCF) ion, and by subsequent heat-treatment. The structural and thermal properties have been systematically studied by thermal analysis, powder XRD, IR spec-troscopy, and XAS. The gallery height of~6.8 $\AA$ upon intercalation of the TCF ion suggests that the $Cr_3O$ plane is parallel to the aluminosilicate layers. Even though the basal spacing of TCF intercalated clay decreases slightly upon heating, the layer structure was retained up to $550^{\circ}C$ as confirmed by XRD and TG/DTA. Ac-cording to the EXAFS spectroscopic analysis, it is identified that the (Cr-Cr) distance of 3.28 $\AA$ between vertex-linked CrO6 octahedra in TCF splits into 2.64 $\AA$, 2.98 $\AA$, and 3.77 $\AA$ due to the face-, edge-, and corner-shared CrO6 octahedra after heating at $400^{\circ}C$, implying that a nano-sized chromium oxide phase was stabilized within the interlayer space of clay.

MAGNETISM OF NANOCOMPOSITE CoSm-BASED FILMS

  • Shan, Z.S.;Liu, Y.;Jeong, S.Y.;Zhang, Y.B.;Al-Omari, I.A.;Sellmyer, D.J.
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.702-709
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    • 1995
  • In this paper we review recent work in our laboratory on nanocomposite CoSm-based films including CoSm with Cr underlayer (CoSm//Cr), exchange-coupled magnetic films consisting of CoSm and FeCo layers (CoSm/FeCo), and CoSm multilayers with nonmagnetic spacing layers of SmO (CoSm/SmO). The emphasis is on detailed investigations of microstructure and magnetic properties for CoSm//Cr films, exchange-spring effects for CoSm/FeCo films, and interlayer effects for (CoSm/ SmO) multilayers.

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Black Phosphorus Nano Flake Lithium Ion Battery Using Electrophoretic Deposition (전기영동 증착법을 이용한 Black Phosphorus Nano Flake 리튬이온 배터리)

  • Kim, Juyun;Park, Byoungnam
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.32 no.3
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    • pp.252-255
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    • 2019
  • Black phosphorus (BP) is a potential candidate for an anode in lithium ion batteries due to its high theoretical capacity and the large interlayer spacing in the monolayered phosphorene form, allowing for lithium intercalation/deintercalation. In this study, large-scale exfoliation of bulk BP was accomplished using a solution of NaOH and N-methyl-2-pyrrolidone (NMP), yielding phosphorene, which can be assembled into nanoflakes using electrophoretic deposition (EPD). Through the systematic addition of NaOH and subsequent sonication, BP nanoflakes were obtained in high yields by EPD, allowing for the integration of these nanoflakes into an anode in the film state. Anodes with a charge/discharge capacity of 172 mAh/g at a rate of 200 mA/g were obtained, which are promising for battery applications through various post-film treatments.

Development of Particle-level Computer Assisted Instruction Materials for the ‘Solution’ Chapter in High School Chemistry Textbook and Analysis of the Educational Effects (고등학교 화학 교과서의 ‘용액’ 단원에 대한 입자 수준의 컴퓨터 보조 수업자료 개발 및 적용 효과 분석)

  • Baek, Seong-Hye;Kim, Jong-Hyeon;Kim, Jeong-Won;Park, Chan-Geun
    • Journal of the Korean Chemical Society
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    • v.50 no.2
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    • pp.163-177
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    • 2006
  • Alpha Nickel hydroxide samples have been synthesized by electrodeposition on platinum and nickel substrates at current densities of 1, 5, 6, 7 and 10 mAcm?2 at a controlled temperature of 30.00 oC from Ni(NO3)2 bath. Platinum substrate shows a tendency to incorporate less nitrate ions with increase in current density thus producing less hydroxy-deficient nickel hydroxide layers. On the whole the interlayer distance (d003) is found to be inversely proportional to the amount of nitrate ions incorporated in-between the lattice. For the first time we have observed a decrease in lattice spacing with increase in concentration of intercalant (anions) and the reason for lattice contraction is attributed to the columbic attractive forces exerted by the oppositely charged nitrate ion and positively charged slabs. The Infrared spectra of the samples with expanded interlayers show two types of OH vibrations corresponding to hydrogen bonded and non-hydrogen bonded OH groups whereas the contracted interlayers show only hydrogen-boded OH groups. Although the faradaic efficiency is found to increase with increase in applied current there is a local minimum at 6.0 mAcm?2 current density on both platinum and nickel substrates. In this manuscript, GC-MS data is provided which clearly demonstrates the electrodeposited nickel hydroxide sample to consist of huge amount of carbonate ions although the electrolyte solution in nickel nitrate.

Intercalation behavior study of ibuprofen/clay organic-inorganic nanocomposites as drug release system (약물 방출 시스템으로서 이부프로펜/클레이 유-무기 나노복합체의 층간삽입 거동 연구)

  • Choi, Bong-Seok;Kim, Dong-Hyun;Kim, Tae-Wan;Jin, Heoyng-Ho;Park, Hong-Chae;Yoon, Seog-Young
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.6
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    • pp.240-245
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    • 2011
  • This research focused on the intercalation behavior of recrystallized ibuprofen into clay as a sustained release drug carrier. The intercalation behaviors of ibuprofen were determined by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The basal spacing ($d_{001}$) of clay increased from 1.2 nm to 1.5 nm by ibuprofen molecules. The segmental motion effect of ibuprofen into the clay interlayer spacing also increased the thermal stability of the ibuprofen/clay nanocomposites. The in vitro drug release results of nanocomposites showed that ibuprofen was released from clay steadily.

The Kinetics of Montmorillonite Expansion in the Treatment with Hexadecyltrimethylammonium (HDTMA와 반응하는 몬모릴로나이트의 팽창 속도론)

  • Lee Seung Yeop;Cho Won Jin
    • Journal of the Mineralogical Society of Korea
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    • v.17 no.4
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    • pp.299-307
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    • 2004
  • Surfactant adsorption by two montmorillonite types with different interlayer cations of Ca and Na was characterized by examining the time dependence of surfactant behavior on the clay surfaces. Surfactants with different micelle concentration were conducted in our experiment to observe a nonequilibrium activity of cationic surfactant on the clay over reaction periods ranging from 0.1 min to 11 days. As compared with Ca-montmorillonite (SAz), a more active intrusion of surfactant molecules into the interlayers was found in Na-montmorillonite (SWy). During a short 'initiation' stage, the basal spacing of SWy montmorillonite increased rapidly with logarithmic time. For SAz montmorillonite, however, the abrupt basal spacing increase occurred at the later stage of the reaction. From the result, the difference in the adsorption behavior exhibited by the two montmorillonite types partly results from their intrinsic nature, that is, inorganic cations originally existing on the clay surfaces. Additionally, the micelle concentration of surfactants affects the development of organo-montmorillonite, especially, in the intercalant formation and stabilization under nonequilibrium.

Study on Synthesis of Pine Leaf Extract Intercalated Mg-Phyllosilicate Sandwich Nanoparticles and Antimicrobial Activity against Cutaneous Microorganisms (솔잎 추출물이 삽입된 마그네슘-층상규산염 샌드위치 나노입자의 합성과 피부 상재균에 대한 항균 특성에 관한 연구)

  • Kim, Seong Yeol;Choi, Yoo-Sung
    • Applied Chemistry for Engineering
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    • v.30 no.2
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    • pp.254-259
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    • 2019
  • In this study, we synthesized the pine leaf extract intercalated layered Mg-phyllosilicate nanoparticles (PLE/MgP) via one-pot synthesis. MgP was successfully synthesized with the octahedral and tetrahedral structure by XRD analysis and a gap of interlayer distance (d-spacing) between MgP sheets by the intercalation of PLE was confirmed. As a result of the investigation of antimicrobial activity against cutaneous microorganisms by the minimum inhibitory concentration (MIC) and bactericidal concentration (MBC) analyses, the antimicrobial activity of PLE/MgP was more improved than that of MgP or PLE. The prepared sandwich-structured PLE/MgP organic/inorganic hybrid materials will be useful in the field of numerous applications containing cosmetic and biomedical materials.