Thermo-oxidative decomposition of multi-walled carbon nanotubes: Kinetics and thermodynamics

Multi-walled carbon nanotubes (MWCNTs) are familiar well owing to their capability of finding wide-reaching applications based on their fascinating properties. Kinetics of thermally activated processes in MWCNTs can help in understanding and controlling those processes which might eventually lead to develop materials with optimized efficiencies. Even though, inadequate information on the kinetics of thermal decomposition of WMCNTs has been reported in the literature, and its thermodynamics is yet to be addressed. In this regard, the present study deals with a detailed kinetic investigation on the thermo-oxidative decomposition of MWCNTs by employing advanced kinetic approaches. Kinetic analysis of MWCNTs decomposition reveals that although the kinetic triplets remain comparable, reaction model under isothermal condition is not the same as under non-isothermal conditions. It alters from contracting cylinder (non-isothermal) to random nucleation followed by isotropic growth of particles (isothermal). Thermodynamics of MWCNTs thermal decomposition points out that the process is non-spontaneous with enhanced endothermicity. In addition, the structure of activated complex is found to be relatively more organized in comparison with the reactant. An account of the interpretations of the obtained kinetic and thermodynamic parameters is also given and discussed in this study.