Surface properties of fumed silica/pyrocarbon prepared by pyrolysis of methylene chloride

The series of pyrocarbon/fumed silica (CS) samples having different carbon concentrations (2.6–53 wt.%) synthesized by means of pyrolysis of CH2Cl2 at fumed silica substrate (SBET=232 m2/g) was studied by TEM, DTG and nitrogen adsorption–desorption methods. On CH2Cl2 carbonization, the disordered carbon deposits can form mainly in the interparticle volume of fractal aggregates of primary particles and their agglomerates; therefore, a significant reduction in the pore volume and the specific surface area is observed with increasing carbon concentration (CC). Porous structure of the tested samples and features of decomposition of pyrocarbon on heating are in correlation with morphology and topography of the adsorbents.