Abstract
In this work, carbon nanotubes were prepared using catalysts consisting of nickel particles supported on the naturally occurring minerals diatomite and shungite. The carbon source for the chemical catalytic vapour deposition (CCVD) synthesis was a propane-butane gas mixture. The synthesized multiwall carbon nanotubes (MWCNT) were characterized using Raman spectroscopy, transmission and scanning electron microscopy, and the effect of temperature on their structure was investigated. The carbon content was determined by thermogravimetric analysis. In Raman spectra of CNTs the intensity ratio I(G)/I(D) for 650 °C is higher than that for 700 °C and then it begins to increase with increasing temperature. The results show that the diameter of CNTs which were synthesized on the surface of diatomite/shungite samples were in the range of 33–100.3 nm. The development of new methods for creating catalytic systems that allow controlling the structure of carbon particles is an important task leading to the improvement of existing approaches to the synthesis of CNTs with certain functional properties.