Preparation of monolithic carbon aerogels and investigation of their pore interconnectivity by a nanocasting pathway

Monolithic carbon aerogels have been prepared using magnesium acetate as catalyst based upon a polycondensation of resorcinol with formaldehyde and an ambient pressure drying followed by carbonization. Carbon aerogels have been synthesized with different catalyst concentration and solid content. The structure of the different aerogels has been investigated in detail by nitrogen sorption measurements, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The surface areas of such carbon aerogels result from the contributions of both mesopores and micropores. The contribution of the micropores to total pore volume is higher than that of samples synthesized with the conventionally used sodium carbonate as catalyst. If a saturated solution of magnesium hydroxide was used as catalyst, the synthesized carbon aerogels almost exclusively consist of micropores and macropores, exhibiting a hierarchical structure. Using the as-prepared carbon aerogels as hard templates, porous silica monoliths can be created by a nanocasting pathway. This demonstrates that carbon aerogels synthesized with Mg2+ as catalyst during the sol-gel process exhibit robust frameworks and improved pore interconnectivity.