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

Abstract

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 °C/min to 15 °C/min, the surface of meso pores showed an increasing trend. With the increase of carbonization temperature from 600 °C to 1200 °C, the micro pore volume decreased. At low carbonization temperature (600 °C), meso pore surface was dominant, whereas at high carbonization temperature (1200 °C), micro pore surface prevailed. According to simultaneous thermal analysis (STA), the carbonization efficiency of the CNT-doped organic gel was about 45 %.