Catalysts supported nanostructures

As a new kind of carbon materials, carbon nanofilaments (tubes and fibers) have been studied in different fields [1]. But, until now far less work has been devoted to the catalytic application of carbon nanofilaments [2] and most researches in this field are focused on using them as catalyst supports. When most of the problems related to the synthesis of large amount of these nanostructures are solved or almost solved, a large field of research is expected to open to these materials [3]. In this paper, CNF is tested as a catalyst for oxidative dehydrogenation of propane (ODP), which is an attractive method to improve propene productivity [4]. The role of surface oxygen annplexes in catalyzing ODP is also addressed. 

Nanostructured Pt(0) catalysts supported on cross-linked macromolecular matrices (Figure 5) have recently been evaluated in the hydrogenation of the a,P-unsaturated aldehyde, ( , Z)-3,7-dimethyl-2,6-octadienal (citral) (Scheme 10) [25]. 

Bruce C. Gates, Supported Nanostructured Catalysts Metal Complexes and Metal Clusters Ralph T. Yang, Nanostructured Absorbents... 

An efficient, low temperature oxidation catalyst was developed based on highly disperse metal catalyst on nanostructured Ti02 support. Addition of dopants inhibits metal sintering and prevents catalyst deactivation. The nanostructured catalyst was formulated to tolerate common poisons found in environments such as halogen- and sulfur-containing compounds. The nanocatalyst is capable of oxidizing carbon monoxide and common VOCs to carbon dioxide and water at near ambient temperatures (25-50 °C). 

Gold Catalysts Supported on Nanostructured Materials Support Effects... 

Duchateau, R. (2003) Silsesquioxanes advanced model supports in developing silica-immobilized polymerization catalysts, in Nanostructured Catalysts, Kluwer Academic/Plenum Publishers, New York, pp. 57-83. 

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). 

However, a serious issue for device integration with CNTs is posed by the inability to control whether the tubes or fibers are semiconducting, semimetallic, or metallic. This aspect will also play a role if carbon nanostructures are used as a catalyst support. Except for a selective destruction of metallic tubes (Collins et al., 2001) an interesting method to separate metallic from semiconducting CNTs is the use of AC DEP. This is done by bringing a suspension of the tubes in contact with a microelectrode array. Due to the different dielectric constant of the species with respect to the... 

SUPPORTED NANOSTRUCTURED CATALYSTS METAL COMPLEXES AND METAL CLUSTERS... 

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