Thermal decomposition kinetics of carbon nanotubes–the application of model-fitting methods

The aim of this work was to study the nonisothermal oxidation kinetics of as-grown and purified carbon nanotubes and to correlate kinetic parameters to their thermal and textural properties. The kinetic analysis was performed by using the TG/DTG experimental data collected in the temperature range from 25 to 1,000 °C at a single heating rate. The data were fitted by using selected model-fitting methods to find an appropriate kinetic model of decomposition. The determined values of activation energy and pre-exponential factor for the as-grown samples confirm different thermal stability among samples, while the different mechanisms of their decomposition are in accordance with tubes specific textural properties. The kinetic parameters confirmed the oxidative stability evolution of CNTs due to the applied purification treatment, however, only for alumina-based CNTs. The kinetics of the purified sample of silica origin could not be analyzed by any of the selected mathematical methods pointing out to another experimental approach.