The production of carbon nanotubes from carbon dioxide: Challenges and opportunities

Abstract Recent advances in the production of carbon nanotubes (CNTs) are reviewed with an emphasis on the use of carbon dioxide (CO₂) as a sole source of carbon. Compared to the most widely used carbon precursors such as graphite, methane, acetylene, ethanol, ethylene, and coal-derived hydrocarbons, CO₂ is competitively cheaper with relatively high carbon yield content. However, CNT synthesis from CO₂ is a newly emerging technology, and hence it needs to be explored further. A theoretical and analytical comparison of the currently existing CNT-CO₂ synthesis techniques is given including a review of some of the process parameters (i.e., temperature, pressure, catalyst, etc.) that affect the CO₂ reduction rate. Such analysis indicates that there is still a fundamental need to further explore the following aspects so as to realize the full potential of CO ₂ based CNT technology: (1) the CNT-CO₂ synthesis and formation mechanism, (2) catalytic effects of transitional metals and mechanisms, (3) utilization of metallocenes in the CNT-CO₂ reactions, (4) applicability of ferrite-organometallic compounds in the CNT-CO₂ synthesis reactions, and (5) the effects of process parameters such as temperature, etc.