Showing papers by "Tewodros Asefa published in 2005"
TL;DR: In this article, gold nanoparticles and Au/SBA-15 nanocoposite with a large density of gold particles in the channels were shown to form nearly monodisperse gold particles.
Abstract: Electroless deposition in SBA-15 forms nearly monodisperse gold nanoparticles and Au/SBA-15 nanocoposite with large density of gold nanoparticles in the channels.
54 citations
TL;DR: In this article, a new class of materials called hybrid periodic mesoporous organosilicas (HPMOs) is proposed by coupling a silsesquioxane precursor through at least two chemical linkages to the mesopore walls of a pre-existing periodic mesophorous silica (PMS) or periodic mesoplastic organosilica (PMO).
Abstract: In this study we report the synthesis of a new class of materials called hybrid periodic mesoporous organosilicas (HPMOs). By coupling a silsesquioxane precursor through at least two chemical linkages to the mesopore walls of a pre-existing periodic mesoporous silica (PMS) or periodic mesoporous organosilica (PMO). Many of the problems of a conventional PMO material can be avoided while ensuring efficient use of the bridging organic functional groups of the silsesquioxane. We demonstrate this concept for PMS by anchoring various silsesquioxanes, such as ethene and ethane silsesquioxanes, to the mesopore walls of the PMS. The addition of anchored silsesquioxane monolayers and multilayers to the mesopore walls also allows for the strict control of the diameter of the mesopore as well as the mesopore wall thickness in the final HPMO material. Additionally it is shown that having the silsesquioxane located solely on the surface of the mesopores in HPMOs gives increased chemical accessibility of the organic bridge-bonded moiety when compared with their PMO counterparts containing the bridge-bonded organic both on the surface and within the pore walls.
50 citations
Patent•
16 Mar 2005
TL;DR: The hybrid mesoporous organosilicas (HOMO) as discussed by the authors is a new class of materials that combine inorganic and organic components organized into a material with mesoscale porosity and having bridge bonded organic, organometallic, or biological functionalized surfaces.
Abstract: The present invention provides a synthetic strategy for creating a new class of materials called hybrid mesoporous, macroporous, or mesoporous-macroporous organometaloxide materials, exemplified but not limited to hybrid mesoporous organosilicas. This strategy involves taking a pre-assembled mesoporous material having a porous framework and then attaching an organic, inorganic or biological guest molecule to the pore walls of the framework material through two or more chemical linkages. The unusual combination of inorganic and organic components organized into a material with mesoscale porosity and having bridge bonded organic, organometallic, or biological functionalized surfaces suggests a myriad of uses for these composite materials, such as the controlled release and uptake of chemicals and drugs, chiral separations and catalysis, electronic printing and microelectronic packaging, thermal and acoustical insulation.
27 citations