In Situ TA-MS Study of the Six-Membered-Ring-Based Growth of Carbon Nanotubes with Benzene Precursor

Abstract

By using the in situ thermal analysis-mass spectroscopic technique, combined with transmission electron microscopic characterization of the carbon nanotube (CNT) product, we have studied the chemical vapor deposition (CVD) growth of CNTs with Fe-Co/gamma-Al2O3 catalyst and benzene precursor in the range of room temperature to 700 degrees C. The growth process has been clearly illuminated, which starts from the reduction of catalyst around 645 degrees C followed by the dissociation of carbon-hydrogen bonds of benzene and the sequential growth of CNTs. A surprising fact is that no possible hydrocarbon species derived from benzene was detected, indicating that the carbon-carbon bond was not broken under our experimental conditions. All of the experimental results strongly reinforce the six-membered-ring-based growth model, and a schematic elucidation is presented accordingly. This in situ study not only reveals the unique and convincing information directly related to the growth mechanism from the involved chemistry, but also provides a powerful way to clarify the mechanism of CVD synthesis of CNTs with other precursors.

Gigas Growth of Carbon Nanotubes

“…The authors have described a probable growth mechanism of CNTs from camphor in an earlier report 13 . Recently, a chinese group 22 carried out in-situ mass spectroscopy of benzene CVD and supported the ring-based CNT growth hypothesis reported by the present authors 13 .…”

Vertically Well‐Aligned In2O3 Cone‐Like Nanowire Arrays Grown on Indium Substrates

“…The reason for the formation of the conelike NWs can be explained according to the proposed growth mechanism below. Similar to the growth of carbon and CNx tubes by surface diffusion, [27][28][29][30] we speculate that, after the "Primary orientation growth" stage, growth by surface diffusion may also be part of the growth process (Figure 4f) axis. In addition, the surfaces of the cone-like In 2 O 3 NWs as shown in Figure 2c have some exiguous nanoparticles, which also support the surface diffusion mechanism.…”

Stable three-dimensional metallic carbon with interlocking hexagons

“…Both share the common feature that they have hexagons as the building blocks. In fact, it has been reported that carbon nanotubes can be synthesized by directly using benzene molecules that, on dehydrogenation, leave hexagonal C 6 (25,26). When a nanotube is unzipped by catalysts, it becomes a graphene sheet.…”