中文
Published date:2014-07-16    Provided by:School of Science
 
Title: Nanoporous materials for Adsorption and Catalysis
Guest SpeakerProfessor Song Weiguo, Chemical Institute of Chinese Academy of
Sciences
Time2014-6-18, 15:00-16:00
LocationYF108
Content &Introduction 
Nanostructured metal oxides with hierarchical structures may satisfy our requirements for desired materials for adsorption of pollutants, Including inorganic metal ions and organic wastes. We developed several general synthesis routes to synthesize metal oxides with desired morphologies and hierarchical structures. These methods include poly-ol mediated route, surfactant assisted aqueous route, hydrothermal route. These routes provide general, reliable and environmental friendly method to prepare a series of transitional metal oxides and rare earth metal oxides, including iron oxide, titania and ceria. These materials are overall micron sized particles that are consisted of assembled or self assembled nano building blocks. The nano building blocks provide high surface area, high surface to bulk ratio as well as surface functional groups that can interact with heavy metal ions and organic species; while the overall micron structures provide desired mechanical properties, such as robustness, facile specie transportation, easy recovery and regeneration. These features are suited for environmental applications.
Diffusion is the key in heterogeneous catalysis. In liquid-solid interfacial reactions, the diffusion of reaction species through surface to the active sites is as important as the active sites. Mesoporous catalysts, especially those with ordered mesopores are ideal for diffusion control. The size of the mesopore, the length of the mesopores, the opening of the mesopores can all be used to control the diffusion within the mesopores. In addition, the spatial location of the active within the mesopores can be controlled to suit the diffusion path of the multi-step reactions for optimal catalysis results. Two examples will be presented. One is the solid-liquid interfacial hydrogen bond catalysis in which in which solid metal hydroxide nanoparticles or metal oxide nanoparticles show superb activity in acid base catalysis due to abundant surface hydroxyl groups and mesoporous structures. The other example is the noble metal catalysis using mesoporous silica as support, in which the mesoporous silica hollow spheres was modified to control the diffusion path to the Pd or Au nanoparticles.