Реферат: The quality of multi-walled carbon nanotubes (MWCNTs) is a complex parameter consisting of different properties of individual tubes and their structure: defect concentration within graphene blocks forming nanotube walls, nature and relative amount of functional groups on the nanotube surface, accessibility and content of catalyst remains, etc. The development of MWCNT synthesis in the reactors with fluidized beds has shifted the attention from the price to the properties of the nanotubes. Taking into account that any potential application requires nanotubes with specific characteristics, influence of catalyst nature and growth conditions on MWCNT quality becomes a key factor to be solved. However, MWCNTs are class of materials with wide range of properties. This restrains the development of fine theoretical models for MWCNT structure. E.g. Raman spectroscopy theory - one of the most common and suitable express methods to study nanotube structure – mostly deals with more convenient nanocarbons: graphene and single-walled carbon nanotubes. Thus, only phenomenological experimental approach can be applied nowadays to examine MWCNTs. Most of the corresponding models consider the ratio of intensities of G and D bands of MWCNT Raman spectra as a metric for defective structure. However, as it was already shown for graphene and single-walled carbon nanotubes, the of G/D ratio as a function of defect concentration has extremum, providing certain ambiguity without additional studies. Moreover, the G band is strongly affected by “saturation” of carbon defects with hydrogen. Here we present the systematic study of the ratio of 2D and D bands of MWCNT Raman spectra. The influence of the catalyst particle size and chemical nature (Fe, Co, Mo, Mn, and their combinations), reaction temperature, posttreatment (defect annealing, ball milling) have been studied from the 2D/D point of view. The model of nanotube structure and Raman metrics for MWCNTs has been proposed.

Библиографическая ссылка: Krasnikov D.V. , Kuznetsov V.L. , Bokova-Sirosh S.N. , Kazakova M.A. , Tsendsuren T. , Romanenko A.I. , Moseenkov S.I. , Obraztsova E.D.
Standardization of the Defectiveness for Multi-Walled Carbon Nanotubes via Raman Spectra
19th International Conference on the Science and Application of Nanotubes and Low-dimensional Materials 15-20 Jul 2018