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Adsorption of H 2 PdCl 4 from aqueous solutions on the surface of graphite-like carbon materials proceeds through two competitive pathways: reduction, which gives rise to Pd 0 particles of 6-100 nm in size, and formation of π-complexes of PdCl 2 with >C=C< fragments of the carbon matrix:Process (1) is localized near the exterior surface of the porous carbon particles...
The surface acidity of several activated carbons was evaluated using the Boehm and potentiometric titration methods. Experimental conditions (particle size, rate of titration) were varied and several procedures to collect raw data for proton binding isotherms (slow continuous addition of titrant, incremental addition conditioned by a pH stability criterion and batch experiments) were compared. Proton...
A recent paper has described the structure of a hypothetical 3-, 4-connected net termed glitter. This is a model of a metallic form of carbon. That paper pointed to the importance of through-space pσ interactions of adjacent olefin units in the net in understanding the electronic structure at the Fermi level. The present communication elucidates the role of spiroconjugation in understanding features...
The intercalation of alkali metals (Li, K, Rb and Cs) into natural graphite flakes in the solutions of 2-methyltetrahydrofuran (MeTHF) and 2, 5-dimethyltetrahydrofuran (diMeTHF) containing naphthalene has been studied by X-ray diffraction (XRD), where naphthalene is used as a dissolving agent for alkali metals. When MeTHF is used as a solvent, binary Li- and K-graphite intercalation compounds (GICs)...
The effect of the separation distance between the aromatic ring systems on the electronic properties of carbons were simulated by model compounds. The model compounds included perylene nuclei separated by aliphatic chains with varying numbers of methylene groups. They were prepared by polycondensation of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and ω-diamines with various lengths of methylene...
The present work is focused on the influence of the severity of heat treatment of coals during pyrolysis and/or early stages of carbon oxidation on the reactivity of the resulting char towards further gasification. Thermogravimetric analysis has been directed to characterize the reactivity of heat treated samples of a bituminous coal in atmospheres containing different carbon dioxide partial pressures...
Silica-carbon (SC) hybrids of varying composition have been prepared by a cyclic two-step process which consisted of: (1) initially adsorbing silicon tetrachloride onto the surface of porous carbon particles, and (2) converting silicon tetrachloride into silica via reaction with water vapor. At the completion of each cycle all samples were studied by thermogravimetric analysis and 29 ...
Boron oxide (B 2 O 3 ) has been impregnated into a high-density isotropic graphite block and a felt carbon fiber reinforced carbon composite (C-C composite). Impregnation was carried out at 1200°C under a pressure of 15 MPa for 1 hour. The bulk density of the original graphite and C-C composite increased by 12% and 20% respectively as a result of impregnation. The mechanical properties...
By DC arc-discharge evaporation of graphite in the presence of rarefied hydrogen gas, not only carbon nanotubes but also petal-like graphite sheets were produced on the graphite cathode as a carbon deposit. A large number of interlaced petal-like graphite sheets were observed by scanning electron microscopy on the cathode surface which surrounded the region of carbon deposit including multiwalled...
The formation of diamond surface radicals and their destruction has been investigated using electron paramagnetic resonance (EPR) spectroscopy. The similarity in behavior of diamond paramagnetic susceptibility and thermodesorption with heat-treatment temperature indicates that the formation of paramagnetic centers is a result of the desorption of oxy-functional groups in connection with the simultaneous...
A composite of electrochemical carbon with LiF was prepared by cathodic defluorination of poly(tetrafluoroethylene). The extraction of LiF was carried out in aprotic medium employing the acetonitrile-BF 3 adduct. The isolated carbon material was derivatized by three different carbenes: CH 2 , PhCH (Ph = phenyl) and CF 3 (CH 3 )C . The products were characterized...
Poly(ethylene oxide)-intercalated graphite oxides (PEO-intercalated GOs) with two differentc -axis repeat distances have been synthesized and characterized in detail. IR spectra and X-ray diffraction patterns obtained at various temperatures of PEO-intercalated GO samples with two different I c values suggest that the conformation of the intercalated PEO is gauche in both PEO-intercalated...
The aggregation kinetics of soot particles, collected from three different drain oils after engine tests and dispersed in a base oil, have been studied by static and dynamic light scattering techniques. The engine runs were performed with two different polymeric additives in the lubricating oil to probe their contribution to the soot aggregation. These polymers have the same skeleton, but one of...
The coat-mix (CM) procedure is a process for mixing the filler and binder materials used in the graphite and ceramic industries. Contrary to the normally used processes utilizing mixers, the CM process is a physico-chemical procedure and each filler grain is coated with binder. The steps of the CM procedure are presented and the results of investigations concerning the uniformity of the binder coatings,...
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