Hierarchically ordered mesocellular mesoporous silica materials (HMMS) were synthesized using a single structure-directing agent. The mesocellular pores are synthesized without adding any pore expander; the pore walls are composed of SBA-15 type mesopores. Small-angle X-ray scattering revealed the presence of uniform pore structures with two different sizes. Using HMMS as a nanoscopic template, hierarchically ordered mesocellular mesoporous carbon (HMMC) and polymer (HMMP) materials were synthesized. HMMS was used as a host for enzyme immobilization. To improve the retention of enzymes in HMMS, we adsorbed enzymes, and then employed crosslinking using glutaraldehyde (GA). The resulting crosslinked enzyme aggregates (CLEAs) show an impressive stability with extremely high enzyme loadings. For example, 0.5 g alpha-chymotrypsin (CT) could be loaded in 1 g of silica with no activity decrease observed with rigorous shaking over one month. In contrast, adsorbed CT without GA treatment resulted in a lower loading, which further decreased due to continuous leaching of adsorbed CT under shaking. The activity of crosslinked CT aggregates in HMMS was approximately 10 times higher than that of the adsorbed CT, which represents a 74-fold increase in activity per unit weight of HMMS due to higher CT loading. 相似文献
A simple template-free synthesis of unique mesoporous titania materials is reported. The synthesis presented is a good, easy and inexpensive method to obtain both ordered and disordered mesoporous titania with tunable and well defined physicochemical properties such us surface area, porosity and crystallinity. The locally-ordered obtained titania was applied as electrode material in dye-sensitized solar cells. The materials prepared were characterized with both wide and small angle XRD, nitrogen adsorption–desorption isotherms, diffuse reflectance UV-Vis, TEM, HRTEM, FT-IR, TGA and DSC measurements. The presented materials showed good activity in photon-to-current conversion process, with overall photoelectric conversion efficiencies reaching up to 5% with fill factors around 60%. 相似文献
Spheroidal ordered mesoporous carbon materials with diameter of 2–10 μm were synthesized by direct carbonization of silica/triblock copolymer P123/butanol composites using P123 and butanol as the structure-directing agents and carbon precursors. The morphologies, structures and pore characteristics of the carbon materials were investigated by scanning and transmission electron microscopes, X-ray diffraction, and nitrogen sorption. It was found that the material possesses a cubic ordered mesoporous structure with Ia3d symmetry. The butanol addition directly affects the carbon morphology and pore structure. When the mass ratio of butanol to P123 is 0.5:1, the product exhibits a perfectly spheroidal morphology with a specific surface area of 1236 m2 g−1 and a total pore volume of 1.26 cm3 g−1. The formation mechanism of the spheroidal ordered mesoporous carbon materials is discussed briefly. 相似文献
Sandwich-type ordered mesoporous carbon/graphene nanocomposites were successfully synthesized using 2D ordered mesoporous silica/graphene nanocomposites as the hard template and an ionic liquid as a N-rich carbon source. We used an ionic liquid of 1-(3-cyanopropyl)-3-methylimidazolium dicyanamide containing nitrile groups (–CN) in the cation and anion as a carbon precursor for the preparation of the nanocomposites. Nitriles do not decompose under thermal treatment in an inert gas atmosphere, but leave significant amounts of N-rich carbon materials. The nanocomposites had a large surface area (1,316 m2·g–1), an average pore diameter of 5.9 nm, and high electrical conductivity. The nanocomposite electrode showed a high specific capacitance of 190 F·g–1 at 0.5 A·g–1 in 1 M TEABF4/AN electrolyte and a good rate capability between 0 and 2.7 V for supercapacitor (or ultracapacitor) applications.
