Structure of carbonized mesoporous silica gel/CVD-titania

Carbon/titania/silica gels containing different amounts of CVD-titania and carbon deposit were investigated using adsorption/desorption and theoretical methods. Analysis of the low-temperature nitrogen adsorption/desorption data for all the examined samples leads to conclusion that their porosity decrease with increasing amounts of titania and carbon covered the oxide surface not only in pores but also at the outer surface of particles. The influence of the carbon deposit on the changes in an accessible surface area of adsorbents is lower than that of titania due to the difference in the texture of these phases and in features of contacts between the deposit and the substrate particles. These features reflect in complicated dependence of the fractal dimension on the concentrations of carbon and titania.