Synthesis of meso- and macroporous carbon aerogels

Organic and carbon aerogels with of meso- and/or macroporosity were obtained by sol-gel using different precursor/catalyst and precursor/water molar ratios. By polycondensation of resorcinol (R) and formaldehyde (F), wet resorcinol-formaldehyde (RF) gels were prepared. Using CO2 supercritical drying, the RF gels were transformed into organic aerogels and to carbon aerogels by pyrolysis under nitrogen atmosphere. The monolith organic and carbon aerogels were investigated by BET, TEM, AFM, SEM and XRD techniques. When using R/C <= 100, mesoporous carbon aerogels with high BET surface area from 800 to 1100 m(2)/g were obtained, whereas for R/C > 100, the resulting carbon aerogels were mostly macroporous. Moreover, in the case of R/C=1500, graphitic pseudo crystalline forms were identified in the carbon aerogels.