• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1400-1402
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• 2001

• Bulletin of the Korean Chemical Society
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• v.21 no.10
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• pp.1015-1019
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• 2000

• Bulletin of the Korean Chemical Society
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• v.19 no.4
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• pp.397-399
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• 1998

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.100-103
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• 2010

In this study, NO reduction behaviors of copper-loaded mesoporous molecular sieves (Cu/MCM-41) have been investigated. The Cu loading on MCM-41 surfaces was accomplished by a chemical reduction method with different Cu contents (5, 10, 20, and 40%). $N_2/77$ K adsorption isotherm characteristics, including the specific surface area and pore volume, were studied by BET's equation. NO reduction behaviors were confirmed by a gas chromatography. From the experimental results, the Cu loading amount on MCM-41 led to the increase of NO reduction efficiency in spite of decreasing the specific surface area of catalysts. This result indicates that highly ordered porous structure in the MCM-41 and the presence of active metal particles lead the synergistical NO reduction reactions due to the increase in adsorption energy of MCM-41 surfaces by the Cu particles.

• Polymer Science and Technology
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• v.15 no.3
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• pp.303-316
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• 2004

균일한 크기의 미세 기공이 규칙적으로 배열되어 있는 다공성 분자체 물질 (porous molecular sieve materials)은 분자 단계의 물질들을 선택적으로 분리 흡착할 수 있는 장점을 가지고 있으며, 이를 이용하여 다양한 화학 반응의 촉매 및 촉매의 담체로서 널리 사용되어 왔다. 미세 기공 물질은 IUPAC 정의에 따르면 세공의 크기에 따라 기공의 직경이 1.5 nm 미만인 마이크로포러스 물질 (microporous materials), 1.5 nm 이상 50 nm 미만의 메조포러스 물질(mesoporous materials), 그리고 50 nm 이상의 매크로포러스 물질 (macroporous materials)로 나누어진다. (중략)

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.122-126
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• 2018

Mesoporous molecular sieves were prepared by the reaction of $Na_2SiO_3$ and $H_2SiF_6$ using nonionic micelle templates in an aqueous solution. Well-crystalline mesoporous molecular sieves were obtained after several seconds at atmospheric conditions. Powder samples exhibited d-spacing of 3.8-5.1 nm with the sharpness of the d00l peak, showing well-crystalline mesoporous molecular sieves, pore size distributions of 2.5-3.1 nm and large specific surface areas of $290-1,018m^2/g$, depending on types of surfactants. SEM images of samples showed well-divided spherical particles with an uniform size of ${\sim}0.5{\mu}m$ and TEM images demonstrated uniform pores with a worm hole shape.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.463-472
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• 1997

A mesoporous molecular sieve, MCM-41, was synthesized and the effent of various initial pH of reaction mixtures on the synthesis and physical properties of MCM-41 was investigated. Adjustment of initial pH for reaction mixtures was made before starting hydrothermal reaction rather than during the reaction. Highly crystalline MCM-41 which shows pore diameters of $30{\AA}$ to $40{\AA}$ and specific surface areas greater than $1000m^2/g$ has been successfully prepared through a single adjustment of initial pH. Results also suggest that the initial pH adjustment has a significant effect on the formation of MCM-41 with a long-range ordered hexagonal array and an excellent thermal stability. Finally, it is speculated that the adjustment of initial pH might accelerate the dissolution of stable polymeric sodium silicate to highly reactive monomeric sodium silicate resulting in well-ordered MCM-41.

• Journal of the Korean Chemical Society
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• v.52 no.5
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• pp.593-596
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• 2008

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.675-682
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• 2005

Al containing mesoporous molecular sieve (Al-MMS) was synthesized by hydrolysis of $H_2SiF_6$ and $Al(NO_3)_3{\cdot}9H_2O$. The material obtained was characterized by XRD, $N_2$-physisorption. The specific surface area was $981m^2/g$, and the average pore size was uniformity $39{\AA}$. It was confirmed that the acidity of Al-MMS was milder than that of zeolite Y based on the results of $NH_3$-TPD. Active materials, Pt and Pd, were loaded on Al-MMS in order to examine the feasibility of using Al-MMS as a catalyst support in the hydrogenation of aromatic compounds included in the residue oil of a naphtha cracker. The hydrogenation activity of PtPd/Al-MMS has been studied by following the kinetics of the hydrogenation of naphthalene, and by comparing the kinetic parameters obtained with Pt and Pd catalysts supported on the other mesoporous material support and commercial conventional support materials. PtPd/Al-MMS catalyst shows the highest activity of hydrogenation and sulfur resistance. The high activity of PtPd/Al-MMS was confirmed again in the hydrogenation of PGO (pyrolized gas oil), which is residue oil obtained from a naphtha cracker. Therefore, PtPd/Al-MMS can be applied to the hydrogenation of aromatic compounds included in the residue oil of a commercial naphtha cracker commericially.

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.70-75
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• 1997

A wide range (10 < Si/V) of mesoporous vanadium silicate molecular sieves with the MCM-41 structure have been synthesized using vanadyl sulfate as the source of vanadium and characterized by XRD, 51V MAS NMR and 29Si MAS NMR. The increase of the unit cell parameter and the decrease of Q3/Q4 ratio of 29Si spectra with the vanadium content suggest the incorporation of vanadium in the framework of MCM-41 structure. 51V MAS NMR demonstrates that vanadiums in as-synthesized V-MCM-41 are present in the chemical environment of octahedra and octahedral vanadium is decreased and tetrahedral vanadium is increased inversely with raising the calcination temperature. Though the thermal treatment in rotor of hydrated sample resulted in the change from tetrahedral environment to octahedral one and the steaming and the acid treatment affect to the chemical environment of vanadium, the spectrum similar to originally calcined sample is regenerated after recalcination. This indicates that the vanadium is belong to the framework in a relatively exposed site. The best quality XRD pattern of the product of Si/V=27 may be attributable to heterogeneous nucleation mechanism. V-MCM-41's having the Si/V ratio lower than 20 are completely collapsed after calcination.