Carbon Nanotube Synthesis via the Calciothermic Reduction of Carbon Dioxide with Iron Additives

The novel fabrication of multi-walled carbon nanotube (MWCNT)/cementite (Fe 3 C) nanocomposites was demonstrated via the calciothermic reduction of carbon dioxide (CO 2 ) through electrolysis in molten CaCl 2 /CaO with iron additives at 1173 K. In this technique, CO 2 generated from a graphite anode is reduced to carbon with a metallic calcium reductant formed on a graphite cathode via electrolysis in molten salt. Calciothermic reduction without iron additives resulted in the formation of onion-like carbons (OLCs) with spherical graphite layers and thin graphite sheets. In contrast, MWCNT/Fe 3 C nanocomposites and OLCs were successfully fabricated via calciothermic reduction with iron additives through their catalytic activities.