Study of oxygen influence in the production of single-wall carbon nanotubes obtained by arc method using Ni and Y catalyst

Abstract

Single-wall carbon nanotubes were produced by arc method (He atmosphere) using Ni/Y 2O 3 and NiO/Y 2O 3 catalysts. The samples obtained by both the catalysts were collected in two regions of reactor: collar and walls zones. The raw material was also submitted to ultrasonic and filtration treatments using a surfactant aqueous solutions of sodium dodecyl sulphate. Raman scattering and transmission electron microscopies were used as characterisation tools. The distribution of carbon nanotube (CNT) content depends on the zone from which samples are collected. In particular the highest CNT content is found in specimens coming from the collar zone when NiO/Y 2O 3 catalyst in employed. In fact, the presence of NiO in the catalyst seems to favour the CNT yield, despite of the consistent amount of the carbon impurities (amorphous carbon and graphite) still present in the raw material. Finally, the surfactant treatment effectively reduces the carbon impurities in the residue thus allowing for an appreciable separation of the CNT component.