A novel combination of simple foaming and freeze-drying processes for making carbon foam containing multiwalled carbon nanotubes

摘要

To fabricate carbon foam with high surface area and electrical conductivity, a novel combination of foaming followed by growth of multi walled carbon nanotubes (MWCNTs) aerogel inside the porous body has been investigated. Open cell sucrose based carbon foam was prepared by thermo-foaming and dehydration at 250 degrees C. A well-dispersed 1.5 wt% MWCNTs aqueous solution in carboxyl methyl cellulose was vacuum impregnated into the porous body and lyophilized using a freeze-drying process. The resulting macro to mesoporous morphology was characterized by scanning electron microscopy and nitrogen porosimetry. Due to the lower thermal conductivity of hydrated carbon foam, the MWCNTs/carbon foam exhibited a random cellular-type morphology with crinkly and curvy sheets of nanotubes. The prepared MWCNTs/carbon foam displayed a very low density of 0.24 g cm(-3) and a fairly high compressive strength of 1.45 MPa. The electrical conductivity being 0.021 S cm(-1), improved eight orders of magnitude compared to that of the dehydrated carbon foam without MWCNTs. Surface area as high as 320 m(2) g(-1) with the pore size distribution centered at 25 and 150 nm and macro to meso porous morphology was achieved which can be considered for various energy storage and environmental applications. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.