Bamboo-type carbon nanotube solids derived from low-cost epoxy resins and their potential application for air filtration

Carbon nanotubes (CNTs) are formed in bulk solids from the thermal decomposition of catalytic amounts of Fe₂(CO)₉ or Co₂(CO)₈ in the presence of an excess amount of a novolac epoxy carbon precursor during the conversion to a shaped thermoset composition and pyrolysis to 1,000 °C. The as-pyrolyzed carbonaceous solid is composed of either Fe or Co nanoparticles embedded in the nanostructured carbon, which contains bamboo-type carbon nanotubes, MWNTs, and some amorphous carbon. The Fe and Co nanoparticles, formed in situ from thermal decomposition of the corresponding salts, are responsible for the formation of the CNTs. The amorphous carbon is removed by selective combustion leaving a high surface area, porous composition. The pore network facilitates the transport of gaseous molecules such as ammonia to the adsorptive sites at the CNT surface and at entrained Fe or Co nanoparticle sites. During the combustion, the Fe and Co nanoparticles are oxidized to the corresponding nanostructured oxides, which are more receptive to ammonia absorption relative to the reduced metal. The ability to produce nanostructured solid compositions containing CNTs in any shape or form from inexpensive, commercially available carbon precursors is facilitating the development for application such as energy, gas sorption, chemical sensor, membrane, and nanodevices.