김지만 교수

Mesoporous molecular sieve MCM-41 with a Si/Al ratio of 39 was obtained by hydrothermal synthesis with a gel composition of 6 SiO2:0.1 Al2O3:1 hexadecyltrimethylammonium chloride:0.25 dodecyltrimethylammonium bromide:0.25 tetrapropylammonium bromide:0.15 (NH4)(2)0:1.5 Na2O:300 H2O. The MCM-41 sample incorporating aluminum (AlMCM-41) was calcined in O-2 flow at 813 K and subsequently ion exchanged with Na+, K+, Ca2+, and Y3+. Th, ion exchange levels have been increased as high as 0.41 Na/Al, 0.36

This review summarizes organic molecule-based electrode materials for rechargeable batteries.

Truncated rhombic dodecahedral crystals of the mesoporous molecular sieve MCM-48 are synthesised by a hydrothermal procedure using sodium silicate, hexadecyltrimethylammonium bromide and various kinds of alcohol.

The formation of mesoporous silica materials has been studied using blends of diblock (CnH2n+1(OCH2CH2)xOH, CnEOx, n = 12 − 18 and x = 2−100) and Pluronic triblock (EOxPO70EOx, x = 5−100) amphiphilic block copolymers as the structure-directing agents and sodium silicate as the silica source. The mesostructure of the silica materials thus obtained, as determined by X-ray diffraction and transmission electron microscopy, changes as the volume of the hydrophilic EO group of the surfactant increases

A commercially important synthetic approach to highly ordered mesoporous silica materials (SBA-family) with 2-D hexagonal (P6mm), 3-D hexagonal (P63/mmc) and cubic (Im3m and Pm3m) structures, using sodium silicate as the silica source and amphiphilic block copolymers as the structure-directing agents is demonstrated.

Highly ordered mesoporous silica can be regenerated from a mesoporous carbon CMK-3 that is a negative replica of mesoporous silica SBA-15, indicating reversible replication between carbon and inorganic materials.

Recently, we reported on the improvement of hydrothermal stability of mesoporous silica using salts solutions (Ryoo, R.; Jun, S. J. Phys. Chem. B 1997, 101, 317. Ryoo et al. J. Phys. Chem. 1996, 100, 17718). The salt effect has been reinvestigated here to solve problems of poor reproducibility. It turned out that the time-dependent effect was missing in the previous reports. The salt effect required approximately 10 days of treatment at 373 K to give its full effect. The time dependence was a cr

Mesoporous silica structures are of increasing importance as supports for enzymes and molecular organometallic catalysts. For high-surface-area, porous 3-d catalytic supports, the relationship between the exterior particle morphology and the 3-d mesopore structure is of particular significance. This paper describes the designed synthesis of selected morphologies of mesoporous SBA-15, which can be chosen from micrometer sized spheres to hundreds or tens of nanometers sized monodispersed particles

Iron oxide anode materials for rechargeable lithium-ion batteries have garnered extensive attention because of their inexpensiveness, safety, and high theoretical capacity. Nanostructured iron oxide anodes often undergo negative fading, that is, unconventional capacity increase, which results in a capacity increasing upon cycling. However, the detailed mechanism of negative fading still remains unclear, and there is no consensus on the provenance. Herein, we comprehensively investigate the negat

It has been found that mesoporous structures of MCM-41 and MCM-48 disintegrate readily in distilled water around 370 K, while the structures can be stable in 100%-steam of 1 atmospheric pressure at much higher temperatures around 820 K. Thus, the structure disintegration is thermodynamically more favorable in water than under the steaming condition. X-ray powder diffraction and magic angle spinning 29Si NMR spectroscopy indicate that the disintegration of the mesoporous structures in water occur

Current lithium ion battery technology is tied in with conventional reaction mechanisms such as insertion, conversion, and alloying reactions even though most future applications like EVs demand much higher energy densities than current ones. Exploring the exceptional reaction mechanism and related electrode materials can be critical for pushing current battery technology to a next level. Here, we introduce an exceptional reaction with a Co(OH)₂ material which exhibits an initial char

Highly ordered hexagonal silica/block copolymer mesostructured composites have been prepared using syntheses with fluoride over a wide range of pH conditions (pH 0–9), by controlling the rates of hydrolysis and condensation of the tetramethoxysilane silica source.