Specific surface area of hierarchical graphitic substrates suitable for multi-functional applications

A multiscale carbon substrate is fabricated by growing carbon nanotubes (CNT) on multicellular graphitic foam using an intermediate oxide nanolayer. Abundant CNT growth is seen on the surface throughout, including the walls of inner pores. The Brunauer–Emmett–Teller (BET) technique with nitrogen has been used to measure the specific surface area (SSA) of this multiscale structure. It is seen that attachment of CNT provides over a one hundred fold increase in usable SSA of the material with negligible increase in volume and a weight gain of only 2.5%. These results correlate well with semi-empirical predictions obtained by combining analytical modeling and microstructural data.

► Hierarchical porous substrates are fabricated by growing strongly attached carbon nanotubes onto the available surfaces of multicellular graphitic foam.
► This process is shown to provide well over a one hundred fold increase in available surface area with a corresponding weight gain of only about 2.5%.
► The measured increase in specific surface area (SSA) is found to match with earlier predictions based on geometric calculations.
► Increased SSA can be approximated by taking the weighted average of foam substrate and loose multi-walled carbon nanotubes.