The Journal of Physical Chemistry C · 2016 · 79 citations · 48 references
Natural SciencesChemistryMaterials ScienceSurface EngineeringSurface ScienceThermal AnalysisCarbon NanomaterialsCarbon NanotubesDecomposition AnalysisDecomposition ProcessesNanotubesThermogravimetric AnalysisActivation EnergyActivation Energy DeterminationCarbon Nanotube FunctionalizationHydrogen-deuterium ExchangeMulti-walled Carbon NanotubesNitric OxideOxidation MechanismsSurface Functional Groups
The mechanism of thermal defunctionalization of multiwalled carbon nanotubes (CNTs) oxidized by nitric acid was studied. X-ray photoelectron spectroscopy and thermal analysis under different heating rates combined with mass spectrometry of evolved gases (TGA–MS) were used to reveal the transformations on the CNT surface. Hydrogen–deuterium exchange and mathematical handling of TGA–MS curves were carried out to evaluate the impact of a small amount of residual oxygen on CNT defunctionalization. Water, CO, CO 2, and NO/CH 2 O mass curves recorded during TGA–MS study were curve fitted. The resultant peaks were attributed to the different stages of CNT defunctionalization. Deuterium exchanged CNTs allowed one to reveal the mechanism of water release during heating. Kissinger’s model was applied to estimate the activation energy of the decomposition of different functional groups on the surface of CNTs.
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Reaction Kinetics in Differential Thermal Analysis
H.E. Kissinger · Analytical Chemistry · 1957 · 13K citations
Kinetic Parameters from Thermogravimetric Data
A. W. Coats, J. P. Redfern · Nature · 1964 · 6.8K citations