• 한국재료학회지
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• 제28권1호
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• pp.24-31
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• 2018

This study reports an environment-friendly synthetic strategy to process nickel oxide nanocrystals. A mesoporous nickel oxide nanostructure was synthesized using an environmentally benign biomimetic method. We used a natural rambutan peel waste resource as a raw material to ligate nickel ions to form nickel-ellagate complexes. The direct decomposition of the obtained complexes at $700^{\circ}C$, $900^{\circ}C$ and $1100^{\circ}C$ in a static air atmosphere resulted in mesoporous nickel oxide nanostructures. The formation of columnar mesoporous NiO with a concentric stacked doughnuts architecture was purely dependent on the suitable direct decomposition temperature at $1100^{\circ}C$ when the synthesis was carried out. The prepared NiO nanocrystals were coated on cotton fabric and their antibacterial activity was also analyzed. The NiO nanoparticle-treated cotton fabric exhibited good antibacterial and wash durability performance.

• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1381-1384
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• 2005

Surface modification of tridimensional cubic mesoporous silica, SBA-16, was investigated with pendant arm functionalized cobalt diaminosarcophagine (diAMsar) cage complex which covalently grafted onto the silica surface through the silication with sylanol group. The spectroscopic results showed that the mesoporous structure was preserved under the $[Co(diAMsar)]^{3+}$ grafting reaction condition. Successful grafting prevented the cobalt diAMsar cage from leaching out from the SBA-16 support.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3711-3718
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• 2012

Here, we report a chain-length dependent morphology and pore structure tailing of mesoporous silica templated from organogels, which is formed by primary alkylamine and ethylene glycol at room temperature. As the chain length of alkylamine changes from 12 to 18, the resulted materials exhibit a morphology change from layers to spheres and platelets, respectively. SEM and TEM observation revealed that these shapes appear to be inherited from their parent organogels. Further pore structure characterization by nitrogen sorption analysis demonstrates that all the resulted silicas exhibit typical IV isotherms indicative of uniform mesopores, and their pore sizes are dependent on the chain length of alkylamine used.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3730-3734
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• 2010

A simple, inexpensive and less time consuming electrochemical methods were carried out to prepare ordered mesoporous cobalt films. Ordered mesoporous cobalt films were successfully synthesized by templated electrodepostion of hexagonal $H_1$-e Co ion. The electrodeposited mesopores films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), low angle X-ray diffraction (XRD) and voltammetric methods. The applicability of thin films as high - performance super capacitors electrode materials is demonstrated electrochemically using cyclic voltammetry (CV) technique.

• Environmental Engineering Research
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• 제20권4호
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• pp.342-346
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• 2015

Haloacetonitriles (HANs) are nitrogenous disinfection by-products (DBPs) that have been reported to have a higher toxicity than the other groups of DBPs. The adsorption process is mostly used to remove HANs in aqueous solutions. Functionalized composite materials tend to be effective adsorbents due to their hydrophobicity and specific adsorptive mechanism. In this study, the removal of dichloroacetonitrile (DCAN) from tap water by adsorption on thiol-functionalized mesoporous composites made from natural rubber (NR) and hexagonal mesoporous silica (HMS-SH) was investigated. Fourier-transform infrared spectroscopy (FTIR) results revealed that the thiol group of NR/HMS was covered with NR molecules. X-ray diffraction (XRD) analysis indicated an expansion of the hexagonal unit cell. Adsorption kinetic and isotherm models were used to determine the adsorption mechanisms and the experiments revealed that NR/HMS-SH had a higher DCAN adsorption capacity than powered activated carbon (PAC). NR/HMS-SH adsorption reached equilibrium after 12 hours and its adsorption kinetics fit well with a pseudo-second-order model. A linear model was found to fit well with the DCAN adsorption isotherm at a low concentration level.

• Macromolecular Research
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• 제17권9호
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• pp.638-645
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• 2009

We report the effect of the amount of the mesoporous material, SBA-15, on the basic traits of fully aliphatic polyimides (API). For this purpose, water soluble, fully aliphatic poly(amic acid) triethyl amine salts ($PAA_{(s)}$) were prepared and mixed with various amounts of SBA-15. Fully aliphatic polyimide hybrid composites containing the SBA 15-type mesoporous silica were synthesized successfully from bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and alicyclic diamine, 4,4'-methylene bis(2-methylcyclohexylamine). The structure of the hybrid composites was confirmed by IR spectroscopic analysis. Scanning electron microscopy revealed the morphology of the compounds. The hybrid composites exhibited good thermal stability, reasonable transparency, and a low dielectric constant.

• 한국전자현미경학회:학술대회논문집
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• 한국현미경학회 2005년도 제36차 추계학술대회 및 제4회 HVEM 이용자 워크샵
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• pp.61-63
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• 2005

• 한국재료학회지
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• 제20권5호
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• pp.252-256
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• 2010

The study was done to change the morphology and pore size of SBA-15 silica, and the characteristics of SBA-15 silica were investigated with TG-DSC, XRD, SEM, TEM and N2 adsorption-desorption under changing aging conditions. SBA-15 silica having a 2D-hexagonal structure was synthesized and confirmed by SEM and TEM. The structure of mesoporus silica SBA-15 showed a pore having regularly formed hexagonal structure and a passage having a cylindrical shape. This result is in good agreement with the pore forming in XRD and cylindrical shape of the structure in $N_2$ adsorption-desorption isotherm. SBA-15 silica showed a large BET surface area of $603-698\;m^2/g$, a pore volume of $0.673-0.926\;cm^3/g$, a large pore diameter of 5.62-7.42 nm, and a thick pore wall of 3.31-4.37 nm. This result shows that as the aging temperature increases, the BET surface area, pore volume, and pore diameter increase but the pore wall thickness decreases. The BET surface areas in SM-2 and SM-3 are as large as $698\;m^2/g$. However, SM-2 has a large surface area and forms a thick pore wall, when the aging temperature is $100^{\circ}C$ and is synthesized into stable mesoporous SBA-15 silica.

• 청정기술
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• 제12권2호
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• pp.107-111
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• 2006

본 연구에서는 실리카 주형을 사용하여 중형기공성 탄소 재료인 CMK-3와 CMK-5를 제조하였으며 이의 수소 저장량을 측정하였다. 비교 물질로는 탄소 재료 중 수소 저장에 관해 가장 많은 연구가 이루어진 다중벽 탄소나노튜브를 사용하였다. 실험 결과, 탄소체에 흡착되는 수소의 양은 탄소 물질의 표면적과 매우 밀접한 관계가 있으며 표면적이 증가될수록 수소 저장량이 증가함을 확인할 수 있다. 본 연구에서 사용된 탄소 재료 중 CMK-5가 가장 높은 수소 저장량을 나타내었으며 CMK-3, MWCNT 순으로 높은 수소 저장량을 보였다. CMK-5의 경우, 팔라듐을 도핑하였을 때 수소 저장량이 매우 크게 증가하였으며 이는 hydrogen spill-over 효과에 의한 것으로 생각되며 이와 같은 현상은 팔라듐이 도핑된 CMK-5의 수소 저장량을 결정하는데 가장 큰 역할을 하는 것으로 나타났다.

• 한국재료학회지
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• 제24권5호
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• pp.243-248
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• 2014

Silicon-carbon composite was prepared by the magnesiothermic reduction of mesoporous silica and subsequent impregnation with a carbon precursor. This was applied for use as an anode material for high-performance lithium-ion batteries. Well-ordered mesoporous silica(SBA-15) was employed as a starting material for the mesoporous silicon, and sucrose was used as a carbon source. It was found that complete removal of by-products ($Mg_2Si$ and $Mg_2SiO_4$) formed by side reactions of silica and magnesium during the magnesiothermic reduction, was a crucial factor for successful formation of mesoporous silicon. Successful formation of the silicon-carbon composite was well confirmed by appropriate characterization tools (e.g., $N_2$ adsorption-desorption, small-angle X-ray scattering, X-ray diffraction, and thermogravimetric analyses). A lithium-ion battery was fabricated using the prepared silicon-carbon composite as the anode, and lithium foil as the counter-electrode. Electrochemical analysis revealed that the silicon-carbon composite showed better cycling stability than graphite, when used as the anode in the lithium-ion battery. This improvement could be due to the fact that carbon efficiently suppressed the change in volume of the silicon material caused by the charge-discharge cycle. This indicates that silicon-carbon composite, prepared via the magnesiothermic reduction and impregnation methods, could be an efficient anode material for lithium ion batteries.