Oxidized graphite, structure

The effect of oxidation pretreatment and oxidative reaction on the graphitic structure of all CNF or CNF based catalysts has been studied by XRD and HRTEM. From the diffraction patterns as shown in Fig. 2(a), it can be observed the subsequent treatment do not affect the integrity of graphite-like structure. TEM examination on the tested K(0.5)-Fe(5)/CNF catalysts as presented in Fig.2(b), also indicates that the graphitic structure of CNF is still intact. The XRD and TEM results are in agreement with TGA profiles of fi-esh and tested catalyst there is no obviously different stability in the carbon dioxide atmosphere (profiles are not shown). Moreover, TEM image as shown in Fig. 2(b) indicates that the iron oxide particle deposited on the surface of carbon nanofibcr are mostly less than less than 10 nm. 

Electron Diffraction and Electron Microscopy. A limited amount of information regarding graphite structure has been obtained by the use of electron beams. Grisdale (27) has measured the degree of orientation using electron diffraction methods on films of pyrolytic carbon deposited on a silica surface under a variety of conditions. Oxidation of the graphite causes an increase in the degree of orientation. 

Application of composite electrodes in the arc discharge process is a well-known route to metallofullerenes [1], To prepare electrodes, a graphite rod is used to be coaxially drilled, stuffed with mixture of metal oxide, graphite powder and thermosetting resin then annealed under vacuum at ca. 2000°C. Such procedure seems to be laborious whereas the yield of metallofullerenes is low [2]. To increase the yield, composite electrodes structure was varied [2] and new equipment was... 

Structure of the Oxidized Graphite. The oxidizing treatment with sodium hypochlorite produces two effects on the structure of graphite namely (i) etching of the microcrystals resulting in an increase of the number of steps (li) functionalization of the steps i.e. creation of carboxylic and other acidic groups at the extremities of basal planes. 

The present review discusses the results of the H NMR spectroscopy for a wide range of carbonaceous materials (heat-treated and nongraphitizable activated carbons, carbon blacks, exfoliated and oxidized graphites, porous and amorphous carbonized silicas). This technique made it possible to determine the spectral characteristics of organic molecules with diverse chemical properties, as well as of water molecules adsorbed on the surface. These characteristics are compared with the structural properties of the materials under consideration. The calculations done for the majority of the subjects of inquiry gave the values of their free surface energies in an aqueous medium as well as the characteristics of bound water layers of various types. 

One method of oxidizing nanodiamond surfaces has already been presented in Section 5.3.4 as a means of sample purification. The differing reactivity of graphitic and diamond carbon is utilized here. The unordered graphitic structures are oxidized and removed as gaseous products, whereas diamond particles are only modified on their surface. 

The common theme in all five synthetic approaches is the reaction of graphite, in the presence of an oxidant, with small molecular or ionic fragments. These basic building blocks allow easy formation of a two-dimensional system within the interlamellar voids of the sheet like graphite structure. As indicated before, both a suitable oxidant and a suitable counteranion must be present before intercalation can occur. Thus, while neither CIF nor CI2 reacts directly with graphite at RT, they may be used as oxidants to cause intercalation of acids electron-pair acceptor such as BF3 or A1C13 . However, these oxidants cannot facilitate the intercalation of a neutral molecule, which cannot accept an X (= F", Cl ), as for example CCI4.. 

The enthalpy of immersion of carbonaceous materials into water has been correlated with the amount and nature of their surface oxygen functional gronps [272-280]. Since the heat of immersion in nonpolar solvents showed less variation than that in water [279], it indicated a partial perturbation of the graphitic structure on the surface by the oxidation process. On the other hand, the heat of immersion in water increased linearly with the surface oxygen level, indicating that the polarity of the carbon black snrface increased due to the formation of oxygen functionalities on the snrface. 

QBE- 9 is a small initial steam leak followed by slow primary coolant depressurization and SCS cooldown. Thermal transient conditions will be the same as AOO-l(A) with no significant consequences to graphite structures. Oxidation will be less than DBE-8. 

---