نتایج جستجو برای: mesoporous silica of ptl
تعداد نتایج: 21170156 فیلتر نتایج به سال:
Synthesis of Size Distribution Controllable Zeolite Nanocrystals via a Novel Confined Space Strategy
A novel confined-space synthesis method has been developed to synthesize zeolite nanocrystals. Colloidal silica nanoparticles serving as the silica source as well as the hard template were embedded in the mesoporous carbon via in situ polymerization of furfuryl alcohol (FA) in the presence of tri-block copolymer (Pluronic P123), and then reacted with an alkaline aqueous solution (Na2O-Al2O3-H2O...
Mesoporous carbon spheres (MCS) have been fabricated from structured mesoporous silica sphere using chemical vapor deposition (CVD) with ethylene as a carbon feedstock. The mesoporous carbon spheres have a high specific surface area of 666.8 m2/g and good electrochemical properties. The mechanism of formation mesoporous carbon spheres (carbon spheres) is investigated. The important thing is a s...
Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed...
The partial oxidation of methanol to formaldehyde was studied over highly dispersed vanadia supported on mesoporous silica SBA-15 (VOx/SBA-15). VOx/SBA-15 catalysts were prepared by a novel grafting/ion-exchange method and characterized using UV-VISand Raman spectroscopy. The resulting surface vanadium oxide species (0 – 2.3 V/nm), grafted on the inner pores of the SBA-15 silica matrix, consist...
In this paper, a facile method for preparing sub-micron spherical mesoporous silica by the sol-gel process and cationic surfactant cetyltrimethylammonium bromide (CTAB) as a soft template was reported. Moreover, the effect of surfactant concentration on the specific surface area and the total pore volume was investigated. The specific surface area, pore characteristic, morphology, chemical comp...
Pseudomorphism is known as a suitable technique for producing mesoscale pore in silica powders keeping their original morphologies. Herein, silica discs with several millimeter dimensions have been prepared using the same method. This method has been utilized through application of pseudomorphism reaction of preshaped bodies by immersion in a solution containing surfactant and swelling re...
Well-dispersed mesoporous hollow silica-fullerene nanoparticles with particle sizes of ∼50 nm have been successfully prepared by incorporating fullerene molecules into the silica framework followed by a selective etching method. The fabricated fluorescent silica-fullerene composite with high porosity demonstrates excellent performance in combined chemo/photodynamic therapy.
Poly(alkylene oxide)-type block copolymers have been recently shown to be particularly versatile as structure-directing agents for the preparation of ordered large-pore mesoporous silica materials. In principle, the structure direction is achieved through the formation of periodic supramolecular self-assemblies between the polymeric surfactants and a silica source in the aqueous solution. The o...
Spray drying a mixture of silica and polystyrene latex (PSL) colloids above the decomposition temperature of PSL results in the formation of porous silica particles. By appropriate selection of the experimental conditions, such as the use of a tubular temperature, the weight fraction of colloids, and the flow rate of carrier gas, the resulting silica particles contain organized pores with a hex...
A mixed amine pyridine polydentate Fe(II) complex was covalently tethered in hexagonal mesoporous silica of the MCM-41 type. Metal site isolation was generated using adsorbed tetramethylammonium cations acting as a patterned silanol protecting mask and trimethylsilylazane as a capping agent. Then, the amine/pyridine ligand bearing a tethering triethoxysilane group was either grafted to such a p...
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