High-Quality Double-Walled Carbon Nanotube Super Bundles Grown in a Hydrogen-Free Atmosphere

Abstract

High-quality double-walled carbon nanotube (DWNT) super bundles were selectively grown above a bowllike cathode by arc discharge in a hydrogen-free atmosphere. These DWNTs can resist high-temperature (up to 720°C) oxidation in air without additional annealing even after acid treatment, which is due to an in-situ defect-healing effect of the bowl-like cathode and the absence of reactive gases during arc discharge. Selective formation of DWNTs is ascribed to the increased presence of carbon clusters in the enlarged hot plasma region inside the cathode and optimized composition of the catalysts.

A Review of Double-Walled and Triple-Walled Carbon Nanotube Synthesis and Applications

“…By the annealing of molecules encapsulated with the SWNT, it is widely accepted that the arc discharge-produced CNTs exhibit high crystallinity and low defect density [21,[73][74][75][76][77][78][79][80][81][82][83]. While arc discharge-produced DWNTs exhibit a high oxidation temperature close to 800 • C, the defect healing at high temperature was proposed as a justification for the high quality product outcomes [73,74]. In contrast to the high crystallinity of DWNTs, the high temperature also leads to the formation of highly graphitized non-CNT carbon impurities, which are difficult to remove by a simple purification process, such as oxidation and/or acid treatments, rather than the formation of amorphous carbons.…”

Carbon nanomaterials synthesized by arc discharge hot plasma

“…Liu et al [44] confirmed that the DWCNTs with excellent oxidation resistance up to 800 °C can be synthesized by H 2 arc discharge with nickel formate dihydrate as catalyst precursor. However, Huang et al [45] demonstrated that high quality DWCNTs can also be selectively synthesized by the He arc discharge with bowl-like cathode, which is attributed to an in-situ defect-healing effect of the bowl-like cathode and the absence of reactive gases during arc discharge. Sugai et al .…”

Single-walled carbon nanotubes supported Ni–Y as catalyst for ultra-deep hydrodesulfurization of gasoline and diesel

“…Ni-Y/SWCNTs (He) and Ni-Y/SWCNTs (Ar) have the same content of metal, and differ in terms of the content of SWCNTs, see TGA curves in Fig. 3 (the SWCNTs begin to lose weight at 600°C and the finish point is over 800°C) [19,23,25]. But the desulfurization effect of them is similar.…”