Graphene catalyst

Figure 4.19 (a,b) Scanning electron micrographs, (c) transmission electron micrograph, and (d) electron diffraction pattern of the "3D graphene" catalyst. Panels (e)... 

Primo, A. Atienzar, R Sanchez, E. Delgado, J. M. Garcia, H., From Biomass Wastes to Large-Area, High-Quality, N-Doped Graphene Catalyst-Free Carbonization of Chitosan Coatings on Arbitrary Substrates. Chemical Communications 2012,48 (74), 9254-9256. 

Preparation research of SWCNT was also put forth by lijima and his co-worker [3]. The structure of SWCNT consists of an enrolled graphene to form a tube without seam. The length and diameter depend on the kinds of the metal catalyst used in the synthesis. The maximum length is several jim and the diameter varies from 1 to 3 nm. The thinnest diameter is about the same as that of Cgo (i.e., ca. 0.7 nm). The structure and characteristics of SWCNT are apparently different from those of MWCNT and rather near to fullerenes. Hence novel physical properties of SWCNT as the one-dimensional material between molecule and bulk are expected. On the other hand, the physical property of MWCNT is almost similar to that of graphite used as bulk [6c]. 

Physisorption measurements showed that carbon nanomaterials exhibit rather meso- and macroporous structures (maximum micropore fraction, 15% see Table 2.1). The lowest specific surface area was measured with the platelet fiber catalyst exhibiting slightly more than 100 m2/g. The Co/HB material offers 120 m2/g of surface area, and the highest BET value was determined with the Co/ MW catalyst featuring nearly 290 m2/g. Carbon nanomaterials, though, are not really porous, as the space between the graphene layers is too small for nitrogen molecules to enter. The only location of adsorption is the external surface of the nanomaterials and the inner surface of the nanotubes. 

R.S. Weatherup, B.C. Bayer, R. Blume, C. Ducati, C. Baehtz, R. Schlogl, et al., In situ characterization of alloy catalysts for low-temperature graphene growth, Nano Letters, 11 (2011) 4154-4160. 

Siamaki, A.R., et ah, Microwave-assisted synthesis of palladium nanoparticles supported on graphene A highly active and recyclable catalyst for carbon-carbon cross-coupling reactions. Journal of Catalysis, 2011. 279(1) p. 1-11. 

Kim, J.D., et ah, Preparation of reusable Ag-decorated graphene oxide catalysts for decarboxylative cycloaddition. Journal of Materials Chemistry, 2012. 22(38) p. 20665-20670. 

Carbon is unique among chemical elements since it exists in different forms and microtextures transforming it into a very attractive material that is widely used in a broad range of electrochemical applications. Carbon exists in various allotropic forms due to its valency, with the most well-known being carbon black, diamond, fullerenes, graphene and carbon nanotubes. This review is divided into four sections. In the first two sections the structure, electronic and electrochemical properties of carbon are presented along with their applications. The last two sections deal with the use of carbon in polymer electrolyte fuel cells (PEFCs) as catalyst support and oxygen reduction reaction (ORR) electrocatalyst. 

Graphene is also used as catalyst support in PEFCs as it offers high conductivity, facile electron transfer and large surface area [151,152]. The planar structure of graphene allows its edge and basal planes to interact with the nanoparticles of the electrocatalyst [100],... 

The activity of elemental carbon as a metal-free catalyst is well established for a couple of reactions, however, most literature still deals with the support properties of this material. The discovery of nanostructured carbons in most cases led to an increased performance for the abovementioned reasons, thus these systems attracted remarkable research interest within the last years. The most prominent reaction is the oxidative dehydrogenation (ODH) of ethylbenzene and other hydrocarbons in the gas phase, which will be introduced in a separate chapter. The conversion of alcohols as well as the catalytic properties of graphene oxide for liquid phase selective oxidations will also be discussed in more detail. The third section reviews individually reported catalytic effects of nanocarbons in organic reactions, as well as selected inorganic reactions. 

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