Interplay of carbon–silica sources on the formation of hierarchical porous composite materials for biological applications such as lipase immobilization

The porous inorganic materials, with hierarchical structures, find application in many processes where the chemical stability and pore connectivity are key points, such as separation, adsorption and catalysis. Here, we synthesized carbon–silica composite materials, which combine hydrolytic stability of the carbon with the surface chemical reactivity of silica in aqueous media. The polycondensation of carbonaceous and siliceous species from sucrose, Triton X-100 surfactant and tetraethylortosilicate during the hydrothermal synthesis led to the formation of hydrochar composite materials. The subsequent carbonization process of these composite hydrochars gave carbon–silica hierarchical porous materials. The study of the micellar reaction system and the characterization of the derivate materials (carbon–silica composite, carbon and silica) were carried out. The results indicate that synthesis conditions allowed the formation of a silica network interpenetrated with a carbon one, which is produced from the incorporated organic matter. The control of the acidity of the reaction medium and hydrothermal conditions modulated the reaction yield and porous characteristics of the materials. The composite nature in conjunction with the hierarchical porosity increases the interest of these materials for future biological applications, such as lipase immobilization.