Synthesis optimization and characterization of multiwalled carbon nanotubes

The unique properties of carbon nanotubes (CNTs) have suggested applications in a variety of fields. Multiwalled nanotubes were synthesized using chemical vapor deposition (CVD) procedures and subsequently characterized. Reaction parameters such as catalyst type and carrier gas flow rate were optimized to produce well-aligned multiwalled nanotubes with lengths between a few microns to several millimeters. Characterization was performed with scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDS), thermo-gravimetric analysis, and Raman spectroscopy, focusing on composition and purity. Results show the synthesis of high-purity nanotubes of several millimeters in length from iron, nickel, cobalt, and titanium carbide catalysts with thermal stability to above 550°C.