Investigation of Physicochemical and Electrochemical Properties of Single-Walled Carbon Nanotubes Modified with Nitrogen

Composites of the type “nitrogen-containing carbon coating – single-walled carbon nanotubes” were obtained by the treatment of single-walled carbon nanotubes (SWCNT) in a gaseous 40%NH3-1%C2H2-C2H4 mixture at temperatures 600–750 °C. Single-walled carbon nanotubes etched in aqua regia (SWCNTet) and doped with nitrogen (N-SWCNT) were studied by XPS, electron microscopy and IR spectroscopy. Various oxygen-containing functional groups were found to reside on the surface of initial SWCNTet. Upon treatment of SWCNTet in 40%NH3-1%С2Н2-C2H4, polymerization and condensation of hydrocarbons resulted in the formation of a thin nitrogen-containing carbon coating. Specific capacitance per a weight of initial and nitrogen-doped carbon nanotubes in an aqueous electrolyte with 1 M H2SO4 was measured. Specific capacitance of carbon electrodes was found to change symbately with the content of nitrogen-containing functional groups on the SWCNT surface

Synthesis of “Silica – Carbon Nanotubes” Composite and Investigation of its Properties

A new method for synthesis of CNT-SiO2 composite was developed. Oligomethylhydridesiloxane (OMHS) was used as the SiO2 precursor. The presence of active hydrogen in the composition of OMHS made it possible to obtain chemical interaction between the surface of carbon nanotubes and the deposited silica layer. The effect of the silica film on the CNT oxidizing ability was studied. It was found that the oxidation rate of the CNT-SiO2 composite decreases approximately by an order of magnitude in comparison with as-prepared CNT. The morphology and structure of amorphous silica obtained after oxidation of the CNT-SiO2 composite were studied. The thermal stability of the CNT-SiO2 composite was also studied. The CNT-SiO2 composite was found to be thermally stable up to temperatures of 1100-1200 ºC. An increase in the calcination temperature to 1300 ºC leads to segregation of the CNT-SiO2 composite into individual components: CNT and SiO2 particles