Showing papers by "Shinji Inagaki published in 2002"

An ordered mesoporous organosilica hybrid material with a crystal-like wall structure.

Abstract: Surfactant-mediated synthesis strategies are widely used to fabricate ordered mesoporous solids in the form of metal oxides, metals, carbon and hybrid organosilicas. These materials have amorphous pore walls, which could limit their practical utility. In the case of mesoporous metal oxides, efforts to crystallize the framework structure by thermal and hydrothermal treatments have resulted in crystallization of only a fraction of the pore walls. Here we report the surfactant-mediated synthesis of an ordered benzene-silica hybrid material; this material has an hexagonal array of mesopores with a lattice constant of 52.5 A, and crystal-like pore walls that exhibit structural periodicity with a spacing of 7.6 A along the channel direction. The periodic pore surface structure results from alternating hydrophilic and hydrophobic layers, composed of silica and benzene, respectively. We believe that this material is formed as a result of structure-directing interactions between the benzene-silica precursor molecules, and between the precursor molecules and the surfactants. We expect that other organosilicas and organo-metal oxides can be produced in a similar fashion, to yield a range of hierarchically ordered mesoporous solids with molecular-scale pore surface periodicity.

Self-assembly of biphenylene-bridged hybrid mesoporous solid with molecular-scale periodicity in the pore walls.

Abstract: A synthesis of ordered biphenylene-bridged mesoporous material with a crystal-like periodic pore wall structure is reported.

Sulfuric acid-functionalized mesoporous benzene-silica with a molecular-scale periodicity in the walls.

Abstract: Novel sulfuric acid-functionalized mesoporous benzene−silicas with a molecular-scale periodicity in the walls were derived from the mesoporous benzene−silica possessing mercaptopropyl groups by the oxidative transformation of −SH into −SO3H.

Synthesis of Cubic Hybrid Organic−Inorganic Mesostructures with Dodecahedral Morphology from a Binary Surfactant Mixture

Abstract: Synthesis of a cubic ethane−silica hybrid organic−inorganic mesoporous material using a binary surfactant mixture is reported. The system consists of ethane-bridged organosilica (BTME), polyoxyethylene alkyl ether [C12(EO)4; Brij 30], and the octadecyltrimethylammonium chloride (C18TMACl) surfactants in a basic medium. Powder X-ray diffraction analysis along with transmission electron microscope observation revealed a cubic symmetry of the mesophase and is consistent with the Pm3n space group. Scanning electron microscope micrographs of material exhibit a well-defined crystal-like dodecahedral morphology with a uniform particle size of 5 μm. Spectroscopic analyses confirmed that an ethane fragment is covalently linked to silica in surfactant-free material. The nitrogen adsorption isotherm shows a type-IV isotherm with a pore diameter of 28 A and a Brunauer−Emmett−Teller surface area of 744 m2g-1. The presented BTME−alkyltrimethylammonium−C12(EO)4−NaOH−H2O system greatly facilitates the synthesis of cubic...

Titanium containing inorganic–organic hybrid mesoporous materials with exceptional activity in epoxidation of alkenes using hydrogen peroxide

Abstract: Titanium containing ethane bridged hybrid mesoporous materials with uniform hexagonal arrangement are prepared by two different routes and characterized using several analytical techniques. The effect of substitution of bridged silsesquioxane precursors for siloxane precursors on the properties of resultant mesoporous bulk materials are also evaluated and discussed in term of mesoscopic order and oxidation catalysis. The materials are highly hydrophobic and selectively epoxidize the α-pinene to α-pinene oxide (with >99% selectivity) and display high hydrogen peroxide efficiencies.

Preparation, XAFS characterization, and catalysis of platinum nanowires and nanoparticles in mesoporous silica FSM-16

Abstract: Pt nanowires are prepared in mesoporous FSM-16 by photoreduction of H2PtCl6, while H2-reduction of H2PtCl6/FSM-16 at 673 K gives Pt nanoparticles in FSM-16. The Pt nanowires and nanoparticles are characterized by physicochemical methods such as XAFS, TEM, XRD, and XPS. The formation mechanism of the Pt nanowires and the catalytic performance in the water–gas-shift reaction are also investigated.

Organic-Containing Mesoporous Silicas with a Variety of Mesophases and a Periodic Pore Wall Structure

Abstract: In this report we introduce new types of organic-inorganic hybrid mesoporous materials, in which organic and inorganic moieties are distributed homogeneously at the molecular level in the framework, forming a covalently bonded network. Possessing unique surfaces on which both organic and inorganic components are exposed, these materials are expected to have applications in various areas as catalysts, adsorbents and separators, and as hosts for nano-cluster synthesis. The hybrid mesoporous materials showed not only unique surface properties but also unique structural features in micron- or angstrom-scales. Mesoporous materials containing ethylene groups in the main framework formed a variety of particle morphologies of hexagonal rod, spherical, and decaoctahedral shapes in the sizes of 1-10 µm. Mesoporous material containing phenylene groups showed novel crystal-like 7.6 A periodicity in the pore walls. The mesoporous material has periodically arranged hydrophobic-hydrophilic surfaces, which is a great advantage for use as catalyst and host material for inclusion chemistry.