Efficient synthesis of high quality double walled carbon nanotubes and their cost-effective properties

Abstract

In the past decades, layered double hydroxides (LDHs) have become star catalysts for the synthesis of carbon nanotubes (CNTs) and have been used commercially for the mass production of multi-walled CNTs (MWCNTs). Herein double walled carbon nanotubes (DWCNTs) of high quality were efficiently prepared by precisely regulating the stoichiometric ratio of iron in LDHs and coordinating with the chemical vapor deposition (CVD) process. The high I_G/I_D ratio (∼13) in the Raman spectra reflects the highly crystalline structure of such obtained DWCNTs. 2–4 walled CNTs of which two walls are dominant, within 5 nm in diameter, are confirmed by TEM. Thermogravimetric (TG) analysis showed that the purity of the CNTs after purification is about 91.5%. Furthermore, the DWCNTs in this report have high Brunauer–Emmett–Teller (BET) specific surface area (SSA) and electrical conductivity, which give them excellent capacitance performance that far exceeds that of the MWCNT products on the market. This work provides a novel strategy for the synthesis of cost-effective DWCNTs.