• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.415-418
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• 2010

Highly ordered mesoporous silver material was successfully synthesized from a mesoporous silica template (KIT-6) with 3-D channel structure using the nano-replication method. The effects of $H_2$ or $O_2$ pretreatments on the catalytic performance of the mesoporous silver were investigated using a temperature programmed CO oxidation technique in a fixed bed reactor. The mesoporous silver material that was pretreated with $H_2$ exhibited an excellent catalytic activity compared to the as-prepared and $O_2$-pretreated catalysts. Moreover, this present mesoporous silver material showed good catalytic stability. For the CO oxidation, the apparent activation energy of the $H_2$-pretreated mesoporous silver catalyst was $61{\pm}0.5\;kJ\;mol^{-1}$, which was also much lower than the as-prepared ($132{\pm}1.5\;kJ\;mol^{-1}$) and $O_2$-pretreated ($124{\pm}1.4\;kJ\;mol^{-1}$) catalysts.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1096-1098
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• 1999

MCM-41 type spherical mesoporous silica material was synthesized, under basic conditions, in the presence of cationic surfactant as templating species. The cationic surfactants used in this experiment were octyltrimethylammonium bromide, dodecyltrimetylammonium bromide, cetyltrimethylammonium bromide, octadecyltrimethyammonium bromide and cetylpyridium bromide. Specific surface area of spherical MCM-41 was as high as $1500m^2/g$ and the pore size decreased with increasing alkyl chain length of surfactant.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.94.1-94.1
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• 2011

In this work, ordered mesoporous carbons (OMCs) were prepared by the conventional templating method using mesoporous silica (SBA-15) for Pt-Ru catalyst supports in fuel cells. The influence of surface modification on carbon supports on the electrochemical activities of Pt-Ru/OMCs was investigated with different pH. The neutral-treated OMCs (N-OMCs), base-treated OMCs (B-OMCs), and acid-treated OMCs (A-OMCs) were prepared by treating OMCs with 2 M $C_6H_6$, 2 M KOH, and 2 M $H_3PO_4$, respectively. The surface characteristic of the carbon supports were determined X-ray photoelectron spectroscopy (XPS). The electrochemical activities of the Pt-Ru catalysts had been enhanced when the OMCs supports were treated by basic or neutral agents, while the electrochemical activities had been decayed for the A-OMCs supported Pt-Ru.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2560-2564
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• 2011

Mesoporous silicon dioxide (meso-$SiO_2$) was prepared using cetyltrimethylammonium bromide as the structure-directing reagent and tetraethyl orthosicate as the silicon source. The influence of pH value on the adsorption behavior of bisphenol A (BPA) was investigated. The adsorption capacity of BPA onto meso-$SiO_2$ increases slightly with pH value from 2 to 6, and then gradually decreases as further improving pH value. The effect of temperature was also studied, and the adsorption capacity of BPA gradually declines with increasing temperature. The adsorption kinetics and thermodynamics of BPA were examined. It is found that the adsorption of BPA onto meso-$SiO_2$ is in good agreement with Langmuir adsorption model. The rate constant of adsorption is $5.17{\times}10^{-3}g\;mg^{-1}\;min^{-1}$, and the maximum adsorption capacity is as high as 353.4 $mg\;g^{-1}$ at 20 $^{\circ}C$.

• Macromolecular Research
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• v.17 no.9
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• pp.697-702
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• 2009

Mesoporous ethanesilica thin film was prepared using PEO-PLGA-PEO triblock copolymers as structure-directing agents and (1,2-bis(triethoxysilyl) ethane BTESE; bridged organosilicates) as inorganic precursors via one-step sol-gel condensation of ethanesilica precursors. The mesostructure of ethanesilica films is critically dependent on the processing experimental parameters after the hydrolyzed silica sol mixture was spin-cast. This study examined the effects of the block copolymer template/organosilica precursor ratio in the casting solution and aging period before calcination of the mesostructure. It was further demonstrated that mesoscopic ordering of organosilicate thin films is induced by the rearrangement of block copolymer template/organosilica hybrid during thermal decomposition of the PEO-PLGA-PEO triblock copolymer. The mesoporous structure and morphology were characterized by SAXS, TEM and solid-state NMR measurement.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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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.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.210-218
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• 2018

Ethylenediaminetetraacetic acid (EDTA)-functionalized KIT-6 and KCC-1 mesoporous silicas were prepared via post-synthesis grafting and examined for their ability to promote the recovery of rare earth metal ions such as $Nd^{3+}$ from an aqueous medium. The obtained adsorption isotherms were fitted to the Langmuir model, which gave a maximum adsorption of $Nd^{3+}$ ions of 109.8 and 96.5 mg/g for KIT-6-EDTA and KCC-1-EDTA, respectively, at $25^{\circ}C$ and pH 6. The adsorption kinetic profile of KIT-6 was faster than KCC-1. KIT-6 was also proved to be more stable against desorption under acidic regeneration conditions.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3331-3335
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• 2014

We examine the potential use of disordered mesoporous carbon as a functional additive for confining dissolved Li-polysulfides and improving the cycling performance of Li-S batteries. To promote a better understanding of the correlation between the total pore volume of disordered mesoporous carbon and the cycling performance of Li-S batteries, a series of disordered mesoporous carbons with different total pore volumes are successfully synthesized using a commercial silica template. Based on the electrochemical and structural analyses, we suggest that the total pore volume of disordered mesoporous carbon is a predominant factor in determining its capability for either the absorption or adsorption of Li-polysulfides, which is primarily responsible for enhancing the cycling performance. The addition of disordered mesoporous carbon is also effective in enhancing the homogeneous distribution of active sulfur in the cathode, thereby affecting the cycling performance.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.165-165
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• 2013

Nickel oxide was deposited on mesoporous silica by atomic layer deposition (ALD) consisting of sequential exposures to Ni(cp)2 and $H_2O$. NiO/silica samples were characterized by inductively coupled plasma-mass spectroscopy (ICP-MS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), etc. The flow-type reactor was used to measure activity of NiO/silica catalyst for catalytic combustion of toluene. The activity of NiO/silica catalyst was evaluated in terms of toluene removal efficiency and selectivity to $CO_2$ and compared with those of bare nickel oxide nanoparticles. In order to investigate influence of reaction temperature on combustion aspect, the catalytic combustion experiments were carried out at various temperatures. We show that both bare and supported NiO can be efficient catalysts for total oxidation of toluene at a temperature as low as $250^{\circ}C$.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.383-389
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• 2020

Mesoporous silica solid catalysts modified with sulfonic acid were prepared for cationic ring-opening polymerization of octamethylcyclotetrasiloxane (D₄). Two sets of MCM-41 (1.7 and 2.8 nm) and SBA-15 (8.1 and 15.9 nm) with different pore sizes were used as catalyst supports. The surface of silica materials was modified with (3-mercaptopropyl)trimethoxysilane by silylation reaction and oxidized to sulfonic acid. The structures of the prepared catalysts were examined by X-ray diffraction and nitrogen adsorption-desorption. The pore size, specific surface area, and pore volume of the modified solid catalysts decreased slightly. In addition, the modification of the sulfonic acid on the silica surface was confirmed by using infrared spectroscopy and nuclear magnetic resonance spectroscopy. To observe the effect of the particle size on the catalytic activity, it was observed with a scanning electron microscope. The catalysts were used to synthesize PDMS through a ring-opening polymerization of D₄, and the conversion and polymerization rate of the polymerization reaction depended on the pore size, specific surface area, particle size, and particle agglomeration of the catalysts. In order for the polymerization rate, the catalyst prepared with SBA-15 of 8.1 nm pore size had the fastest reaction rate and showed the best catalytic activity.