Monodispersion of Nanoparticles in Channel of Porous Structures and the Related Applications in Catalysis

The controllable fabrication and thermal-stability of the nano-structured particles are currently becoming a very crucial issue concerning the so-called ""nanocatalysis"", and a recent development of super molecular self assembled porous mateials opens a new way obtain well defined guest nanocomposites. In this present report, a niew approach towards monodispersed and thermal stable metal nanoparticles by the nanoconfinement of orderd mesopoorous mateials will be presented , and three successive aspects related will be mainly illustrated. Firstly, we will introduce the recent progress in the functional control of the strucures of the mesoporous materials. Rational tuning of the structures, i.e. morphology, pore size and pore length, by controlling supernolecular self-assembly behavior, will be demonstrated. A novel synthesis of short-pore mesoporous materials is emphasized for their easy mass transfer in both biomolecule absorption and the facile assembly of metal nanocomposites within their pore channels. In the second part, the different routes for encapsulating monodispersed nanoparticles inside channels of porous materials are introduced, which mainly include the ion exchange/conventional incipient wetness impregnation, metal-organic chemical vapor deposition, and schemes making use of the silanols, etc. A facile in-situ auto-reduction route is highlighted to get monodipersed metal nanoparticles with tunable sizes inside the channels of mesoporous silica. Finally, a confinement effect of the channel of mesoporous materials is demonstrated towards improving thermal stability of monodispersed metal nanoparticles catalysts, and a especial emphasis will be focused on he stabilizing the metal nanoparticles with low Tammann temperature. Several catalytic reactions concering the metallic and oxide nanoparticles will be demonstrated, such as the oxidations of methanol over nano-silver catalysts and selectice hydrogenation of CO for forning ethanol over CNT confined Rh-Mn catalysts. It is well revealed that the confinement of the channel structures is rater unique, especially in stabilizing the metal nanoparticles catalysts, which is of great importance in the exploration of size dependent catalytic chemistry, and further understanding the nature of catalytic reactions