One-pot assembling of hierarchical porous carbon/silica nanocomposites for cycloaddition reaction

Hierarchically structured porous materials are of great interest to catalysis, where an accurately controlled pore texture at different length scales is favorable to reduce or otherwise control transport limitations. With one-step assembly of silica and carbon by using varying amounts of tetraethoxysilane (TEOS) as silica source and resorcinol and formaldehyde (R-F) as carbon source, a series carbon and silica nanocomposite materials with hierarchical porous structure (abundant micropores and ordered mesopores) were synthesized. Due to the matching condensation and polymerization rate of TEOS and R-F, carbon/silica nanocomposites (CSNs) with spherical morphology and uniform distribution of carbon and silica can be obtained. However, once the equilibrium point of this condensation and polymerization is deviated, the pore structure and morphology of the materials will be changed. According to the results, in CSNs materials, silica acts as the main structure skeleton, while carbon mainly contributes to the construction of micropores. Furthermore, the resultant CSNs were used as a carrier for the catalyst to support the ionic liquid, thereby catalyzing the cycloaddition of CO2 with epoxide, in which the materials showed high catalytic activity and stability due to the special structure and compositions.