Pseudo-graphite

Before concluding this subject, mention is made here of two more novel approaches for using SBE. Pollard et al. (143) have reported that SBE can be used to prepare a pseudo-graphitic char suitable as a low-cost replacement for activated carbon in the stabilization/solidification of industrial wastes. In their process, they char 2 1 blends of SBE and ZnCl2 at 450°C/1 hour and then activate the material at 600°C/1 hour. The resultant hybrid material is as effective as activated carbon for fixing toxic organics and, because of its aluminosilicate framework, exhibits additional pozzolanic activity in the cement-based stabilization/solidification reactions in which these materials are used. Very recently (144), Bohling reported on... 

Such higher residual activity could be in accordance with the model proposed by Sachtler, which assumes that S is preferentially adsorbed on Re sites in bimetallic Pt-Re particles [20]. Indeed, as the Pt-Re interaction is the highest, sulfur ought to divide the Pt-Re surface into very small Pt ensembles. Consequently, the reorganization of the carbonaceous overlayer into pseudo-graphitic entities, which are detrimental to the metallic function, could be impeded. 

When strongly heated in air absence the diamond either sublimes or is converted to graphite it never melts. The somewhat slippery feel is regarded as due to the assumption by the electronic orbits of surface atoms of a pseudo-graphitic structure. 

The nature of the coke was studied by X-ray diffraction. Fig, 2 shows the spectra of the fresh catalyst (a) and the coked catalyst (b). Compared to that of the fresh catalyst, there is a coke signal in the XRD pattern of the coked catalyst. Fig.3 shows the diffraction patterns of carbon extracted from the coked catalyst. The difference between the XRD patterns of the fresh and coked catalysts and the XRD patterns of the separated coke indicate that the coke probably consists of unorganized aromatic systems and of alkyl chains and alicyclic moeties joined to a polynuclear aromatic system. In conclusion, the carbonaceous matter possibly exists in a pseudo-graphitic structure. ... 

From all the above results, it is inferred that the formation of aromatic compounds from parasite reactions in alkane hydroisomerization play an important role for generation coke precursors, which, during the coke formation, continued their polymerization in the acid sites of the Pd/HM catalyst to be eventually converted into polyaromatic or pseudo-graphitic structures. 

In the third paper by French and Ukrainian scientists (Khomenko et al.), the authors focus on high performance a-MnCVcarbon nanotube composites as pseudo-capacitor materials. Somewhat surprisingly, this paper teaches to use carbon nanotubes for the role of conductive additives, thus suggesting an alternative to the carbon blacks and graphite materials - low cost, widely accepted conductive diluents, which are typically used in todays supercapacitors. The electrochemical devices used in the report are full symmetric and optimized asymmetric systems, and are discussed here... 

Studies of intercalates have also been reported in recent years. In their EXAFS investigation of Btj in graphite, Heald Stern (1978) have found that while the intercalate retains its molecular structure, the Br-Br distance increases so as to match the periodicity of the graphite lattice. In the series of pseudo-stoichiometric alkali... 

Tetrahydroisoquinoline-l-carboxylic acids have been anodically decarboxylated in MeOH-NaOMe on a graphite felt anode, giving 3,4-di-hydroisoquinolines (50-90%)417 This may be an example of a pseudo-Kolbe reaction in support of Hahn s theory of the biosynthesis of isoquinoline alkaloids by providing a laboratory analogy for the crucial decarboxylation step. 

The different biosensors were obtained using thick-film SPEs produced by Biosensor Laboratory, University of Florence and commercialized by PalmSens. The electrochemical cell, consisting of a graphite working electrode and silver counter and pseudo-reference electrodes, was printed on a planar polyester substrate (Fig. 29.2). 

An alternative to the atomization method is what has been called the formation method, which is illustrated for methanol in Fig. 5.27. This method utilizes a kind of pseudo heat of formation , AH f0, of the compound from atomic carbon and molecular hydrogen and oxygen (the conventional heat of formation is relative to graphite and molecular hydrogen and oxygen). 

It has already been mentioned that black phosphorus has a greater electrical conductivity than other forms, and is therefore to be considered as the most metallic variety.2 The conductivity, however, like that of graphite, increases with rise of temperature, and this form is therefore only pseudo-metallic. 

Fig. 2 Screen-printed electrodes produced in the author s lab the cell consists of circular graphite working electrode (diameter of 3 mm), a silver pseudo-reference electrode, and a graphite counter electrode. The cell is printed on a planar, polyester substrate (of thickness 450 micron). Each cell is pre-cut by a laser trim. The dimension of each cell is 0.8 cm x 4.5 cm. A standard connector of 2.45 mm pitch can be used with these cells. These sensors show a coefficient of variation (CV) of 5%...

The smallest approximate pseudo-orthohexagonal coincidence cell (S S ) has the dimensions, the lattice parameters and the space group given. This is related to the component cells by the given matrices - the upper for intercalate, the lower for graphite layers... 

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