| Abstract
| - Carbosil samples at different carbon concentrations CC = 0.5−64 wt % were synthesized by means ofpyrolysis of CH2Cl2 at a fumed silica substrate (SBET ≈ 300 m2 g-1) and studied by using IR, TEM, nitrogenadsorption/desorption, electrophoresis, and photon correlation spectroscopy. During methylene chloridecarbonization, the disordered carbon deposit can form mainly in the interparticle volume of fractal aggregatesof primary silica particles; therefore, a marked reduction in the pore volume and the specific surface areais observed with increasing CC. Changes of the pH(IEP) value and zeta potential ζ(pH) for the aqueoussuspensions of carbosils are relatively small with increasing CC due to the availability of oxidized carbonfragments and the silica patches without carbon coverage. The effective diameter of particles (aggregatesand agglomerates) of X/SiO2 in the aqueous suspensions is larger at X = C than that of mixed oxides atX = TiO2 or GeO2 at a given concentration of the second X phase.
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