Investigation of properties of carbon nanotubes synthesized by nebulized spray pyrolysis Available to Purchase

Multiwalled carbon (C) nanotubes (CNTs) were synthesized by nebulized spray pyrolysis of xylene and ferrocene in a horizontal tube furnace at atmospheric pressure. The reaction temperature and the argon (Ar) gas flow rate were kept constant at 1200°C and 3·5 l/min, respectively, while the hydrogen (H₂) gas flow rate was varied. The as-synthesized CNT films were then purified through peroxide and acid treatment. The samples were characterized with Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry–differential thermal analysis (TG-DTA) and nitrogen (N₂) Brunauer–Emmett–Teller (BET) analysis. Raman measurements revealed a wide D-band and a comparatively narrow G-band, indicating relatively good graphitization of the CNTs, which is supported by TEM measurements and the I _D/I _G ratio of 0·072. TEM measurements exhibited multiple semicrystalline concentric CNTs with an outer diameter of around 33 nm. From radial breathing mode measurements, the diameter of the innermost tube was estimated to be 0·9 nm, consistent with TEM measurements. TG-DTA showed that 47% of the purified CNT sample was amorphous CNTs, 39% was composed of CNTs, 6% was the oxidized catalyst and the remaining 8% was amorphous carbon. Nitrogen BET analysis showed the surface area of the CNT to be 321·5 m²/g, corresponding to a high-porosity CNT sample consistent with SEM measurements.