Deep-injection floating-catalyst chemical vapor deposition to continuously synthesize carbon nanotubes with high aspect ratio and high crystallinity

The deep-injection floating-catalyst chemical vapor deposition (DI-FCCVD) technique is introduced to continuously synthesize carbon nanotubes (CNTs) with high aspect ratio (AR>17000) and high crystallinity (I_G/I_D > 60) at high production rate (>6 mg/min). In this technique all reactants are injected directly and rapidly into high-temperature reaction zone through thin alumina tube; this process leads to simultaneous thermal decomposition of well-mixed catalyst precursors (ferrocene and thiophene), and thus to formation of uniformly-sized catalyst particles. Carbon nanotube fiber (CNTF) fabricated from high-AR CNT has specific strength of 2.94 N/tex and specific modulus of 231 N/tex, which are comparable to those of the state-of-the-art carbon fiber. Both DI-FCCVD and wet spinning methods are easily scalable to mass production, so this study may enable widespread industrial application of CNTFs.