Effect of synthesis conditions on the structural properties of CNT-doped carbon aerogels

Resorcinol-formaldehyde (RF) sol-gels have attracted much attention in the last decade. Carbon aerogels with very light and porous structures can be produced by controlled drying and subsequent pyrolysis of these organic gels under a neutral atmosphere. In general, it is indispensable to tailor the aerogel pore structure according to the application. In this study, some parameters affecting the structure, like the carbon nanotubes doping, heating rate during carbonization process, and temperature of carbonization have been investigated by measuring N2 adsorption/desorption isotherms at 77 K. It was observed that by increasing the amount of carbon nanotubes (CNTs) from 0 mg to 100 mg, the Brunauer, Emmett and Teller (BET) surface area and the total pore volume showed a decreasing trend and then increased again at 180 mg. By increasing the heating rate from 5 degrees C/min to 15 degrees C/min, the surface of meso pores showed an increasing trend. With the increase of carbonization temperature from 600 degrees C to 1200 degrees C, the micro pore volume decreased. At low carbonization temperature (600 degrees C), meso pore surface was dominant, whereas at high carbonization temperature (1200 degrees C), micro pore surface prevailed. According to simultaneous thermal analysis (STA), the carbonization efficiency of the CNT-doped organic gel was about 45 %.

Automated summary

In this study, the structure of the RF sol-gel was investigated by measuring N2 adsorption/desorption isotherms at 77 K. The results showed that the amount of carbon nanotubes, heating rate, and carbonization temperature all have impacts on the pore structure of the aerogel. Increasing the amount of carbon nanotubes initially decreased the surface area and pore volume, but then it increased again. Higher heating rate led to an increase in meso pore surface, while higher carbonization temperature resulted in a decrease in micro pore volume.