Nanostructured zeolites

Shu, S., Husain, S. and Koros, W.J. (2007) Formation of nanostructured zeolite particle surfaces via a halide/Grignard route. Chemistry of Materials, 19 (16), 4000-4006. 

Wang, H. Huang, L. Holmberg, B.A. Yan, Y. Nanostructured zeolite 4A molecular sieving air separation membranes. Chem. Comm. 2002, 1708-1709. 

Yan, Y. Wang, H. Nanostructured zeolite films. Encyclopedia of Nanoscience and Nanotechnology 2004, 7, 763-781. 

Synthesis of Porous Materials Zeolites, Clays, and Nanostructures, edited by Mario L. Occelli and Henri Kessler Methane and Its Derivatives, Sunggyu Lee... 

Self-assembly processes in nature are sometimes catalyzed by enzymes. Zeolites are, in many ways, the inorganic counterparts of enzymes, with their ability to selectively bind other substances and perform catalysis. Can templates or catalysts be effective in increasing rates and reducing defects in a wide range of nanostructured materials ... 

Sudhakar Reddy, J., Dicko, A., and Sayari, A., in Synthesis of Porous Materials Zeolites, Clays and Nanostructures (M. Occelli and H. Kessler, Eds.), p. 405-415. Marcel Dekker, New York, 1997. 

In the following decades, researchers in catalysis turned their efforts to controlhng molecular structure as well as size. The catalyst zeolite paved the way. In the late 1960s, researchers at Mobil Oil Co. were able to s)uithesize zeolite by deliberately designing and preparing the structure of catalysts at the atomic and molecular levels. The resulting nanostructured crystalline material (ZSM-5)—with a 10-atom ring and pore size of 0.45-0.6 nm—enabled the control of selectivity in petrochemical processes at the... 

Within a discussion of nanostructured catalysts, mention must be made of zeolitic systems. Zeolites are a broad family of natural and synthetic aluminosiU-cates that exhibit two important properties that makes them ideal for consideration as heterogeneous catalysts they are crystalline and porous. Crystallinity brings with it precise definition at the atomic scale that is absent with amorphous or polycrystaUine metal oxides. The combination of a well-defined structure and... 

The low-temperature physisorption (type I isotherm) of hydrogen in zeolites is in good agreement with the adsorption model mentioned above for nanostructured carbon. The desorption isotherm followed the same path as the adsorption, which indicates that no pore condensation occurred. The hydrogen adsorption in zeolites depends linearly on the specific surface areas of the materials and is in very good agreement with the results on carbon nanostructures [24]. 

FigureS.18 Hydrogen adsorption isothermsforzeolites (left) and amount of adsorbed hydrogen versus the specific surface area of the samples for zeolites and carbon nanostructures (right).

Synthesis of Porous Materials Zeolites, Clays, and Nanostructures,... 

For the detailed study of reaction-transport interactions in the porous catalytic layer, the spatially 3D model computer-reconstructed washcoat section can be employed (Koci et al., 2006, 2007a). The structure of porous catalyst support is controlled in the course of washcoat preparation on two levels (i) the level of macropores, influenced by mixing of wet supporting material particles with different sizes followed by specific thermal treatment and (ii) the level of meso-/ micropores, determined by the internal nanostructure of the used materials (e.g. alumina, zeolites) and sizes of noble metal crystallites. Information about the porous structure (pore size distribution, typical sizes of particles, etc.) on the micro- and nanoscale levels can be obtained from scanning electron microscopy (SEM), transmission electron microscopy ( ), or other high-resolution imaging techniques in combination with mercury porosimetry and BET adsorption isotherm data. This information can be used in computer reconstruction of porous catalytic medium. In the reconstructed catalyst, transport (diffusion, permeation, heat conduction) and combined reaction-transport processes can be simulated on detailed level (Kosek et al., 2005). 

Figure 3.9 Schematic of the process used by Pinnavaia et al. for the preparation of steam-stable aluminosilicate nanostructures assembled from zeolite seeds, (a) Nanosize zeolites (zeolite seeds) (b) zeolite seeds assembling around the surfactant (CTAB) (c) assembled structure and,...

Dr. Rolison is a member of the American Chemical Society, AAAS, the International Zeolite Association, the Materials Research Society, and the Society for Electroanalytical Chemistry (SEAC). She wrote Ultramicroelectrodes, the first textbook in this very active research area of electrochemistry, with Martin Fleischmann, Stanley Pons, and Peter Schmidt. She and Henry White guest-edited an issue of Langmuir devoted to the electrochemistry of nanostructured materials (February 1999). Dr. Rolison was a member of the Advisory Board for Analytical Chemistry and is a current member of the editorial boards of the Journal of Electroanalytical Chemistry and Langmuir. She is a member of the Board of Directors for the SEAC and has served since 1997 as editor of the society s newsletter, SEAC Communications. 

---