Raman Characteristics of Multiwall Carbon Nanotubes on Diatomite

In this paper, the diatomite mineral from Mugalzhar field, Aktobe region, has been used as a matrix of catalyst particles to synthesize multiwall carbon nanotubes (MWCNTs) by Catalytic Chemical Vapor Deposition method (CCVD). As a source of carbon was used a propane-butane gas mixture, as a catalyst - Ni particles deposited from Ni(NO3)(2) solution during heat treatment process at 400-500 degrees C. The CCVD method was conducted at a different temperature: 650 degrees C, 700 degrees C, 750 degrees C, 800 degrees C. Obtained MWCNTs were studied by Raman spectroscopy. The characteristics such as crystallinity, defectiveness, diameter of MWCNTs synthesized at different experimental conditions were evaluated from the positions and intensity ratios of Raman peaks of the samples. The results of investigations of the properties of the obtained carbon nanotubes show the dependence of MWCNTs characteristics on CCVD method temperature. The observation of changes in all the three peaks -D, G and 2D, of obtained materials exhibit, that MWCNTs synthesized at 800 degrees C possess high crystallinity, low defectiveness and larger diameters as compared with carbon nanotubes grown at 650 degrees C, 700 degrees C, 750 degrees C.