Effects of further adding of catalysts on nanostructures of carbon aerogels

Carbon aerogels were synthesized by poly-condensation of resorcinol–formaldehyde (RF) in a sodium carbonate catalyzed solution, followed by gelation and supercritical drying and carbonization in N2 gas atmosphere. A further adding of catalyst was carried out during the gelation process, in which catalysts of acetic acid and sodium carbonate were used, respectively. Experimental results showed that both the base and the acid catalysts adding can accelerate the gelation stage to about 2 h, shorter than 1 week, at the same time, the acid further adding yielded a broad pore size distribution, while the base further adding produced a sharp one. Carbonization caused no obvious change in the porosity for the acetic acid further adding sample, while the sodium carbonate catalyst further adding sample showed a sharp pore size distribution during carbonization. It was shown that the carbonization could improve the porosity and lead to the successful decrease in the bulk density.