Catalysis carbon materials used

With rapid development of zeotypic materials and mesoporous solids and their application in heterogeneous catalysis, HRTEM shows its advantages in distinguishing the ultrastructural features [40, 41], Carbon materials are used as support in catalytic reactions due to some of their specific characteristics and many publications report the TEM investigations on various forms of carbon related materials [42-48],... 

Amorphous carbon is one of the most important and economical materials in catalysis and is generally used as a support for metallic catalysts. Normally, fine metallic particle catalysts are dispersed on such carbon supports. In the following section we briefly review such carbons, its uses and carbon deposits resulting... 

Most of the adsorbents used in the adsorption process are also useful to catalysis, because they can act as solid catalysts or their supports. The basic function of catalyst supports, usually porous adsorbents, is to keep the catalytically active phase in a highly dispersed state. It is obvious that the methods of preparation and characterization of adsorbents and catalysts are very similar or identical. The physical structure of catalysts is investigated by means of both adsorption methods and various instrumental techniques derived for estimating their porosity and surface area. Factors such as surface area, distribution of pore volumes, pore sizes, stability, and mechanical properties of materials used are also very important in both processes—adsorption and catalysis. Activated carbons, silica, and alumina species as well as natural amorphous aluminosilicates and zeolites are widely used as either catalyst supports or heterogeneous catalysts. From the above, the following conclusions can be easily drawn (Dabrowski, 2001) ... 

The approach of research institutes AGLARG [9] was used for an operative estimation of gas sorption capacity for carbon sorbents. According to it micropore volume and the specific surface area have been chosen as determining parameters. To obtain the function approximating dependence of hydrogen sorption capacity on carbon materials from value of a specific surface area (at pressure 0.1 MPa and temperature 77 K), we used our experimental data (Table 1) and an experimental database (Table 2) of group of institutes - Inorganic Chemistry and Catalysis, Debye Institute, Utrecht University [10],... 

Among the mechanical properties of greatest practical impact on catalysis applications is the attrition and crushing resistance of powdered or granular activated carbons, the most commonly used catalytic carbon materials, versus that of activated carbon fibers (ACFs) or of other, less-surface-active carbons (e.g.. 

In addition to its use as a catalyst support (see Chapter 4), carbon can find applications as a catalyst on its own. Activated carbon catalysts have long been used in the production of phosgene [1,2] and sulfur hahdes [3], The corresponding technologies seem to be well established, although the mechanistic details are not known in detail [4], The only recent pubhcation on this subject concerns the reduction of the by-product carbon tetrachloride using Sibunit (a carbon material developed at the Boreskov Institute of Catalysis) instead of the coconut shell-based activated carbon catalyst [5],... 

Carbon materials have also been used in environmental catalysis for the removal of SO, NO c, and H2S from gaseous streams. Basic carbons were the most active in these processes, particularly N-doped carbons. Linear correlations between the catalytic activity and the concentration of pyridinic groups were reported in the oxidation of SO2 and in the selective catalytic reduction of NO with ammonia. 

An important feature of these materials is that metal-doped monolithic carbon gels can readily be prepared (see below). These are emergent materials in the field of heterogeneous catalysis, and their use will grow in the near future, due... 

Compared to the predominant applications of these carbon materials as adsorbents for drinking water, wastewater, and gas purification, as fillers in rubber production, or as refractory materials, however, their use in the catalyst market represents only a moderate share. The potential growth of the market for carbons in catalysis depends on (1) better understanding of the chemistry of carbon surfaces and fine tuning of the microstructure of these materials, which could then be exploited in the design of truly unique catalysts and (2) improvements in quality control and production methods, to supply constant-quality materials (synthetic carbons). There are additional opportunities to increase the market value of carbon materials in the near future, due to the rapidly advancing development of fuel cells, the use of novel carbon materials, the increasing need for catalytic... 

Since this is a multiauthored book, significant differences in style from chapter to chapter are inevitable, but we have tried to avoid overlaps as much as possible. We thank all the authors for their efforts to meet the deadlines and to follow the format defined for the book. We would also like to acknowledge the assistance of Anita Lekhwani at Wiley, whose advice has been most helpful at the various stages of preparation of the manuscript. Finally, we hope that the book will be useful to fellow scientists and practitioners and will stimulate further research and discussion on the development of carbon materials for catalysis. 

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