Kinetic analysis of the non-isothermal decomposition of carbon monofluoride

• We determine the decomposition of (CF)n is a heterogeneous reaction.
• We determine the kinetic mechanism function of the thermal decomposition of (CF)n.
• Šesták–Berggren model suggests branching nuclei interacting during the nuclei growth.
• We describe the growth of carbon nuclei via a schematic model.
• Amorphous carbon, CF4 and C2F6 are final products of (CF)n decomposition.

The kinetic mechanism of carbon monofluoride ((CF)n) decomposition and the products generated in this reaction were studied. Given the non-isothermal differential scanning calorimetry and thermogravimetric analysis curves, nucleation mechanisms for (CF)n decomposition were proposed using model-free method. According to the extent of conversion of the reaction, the kinetic process could be described by the two-dimensional Avrami–Erofeev equation f(α) = 2(1 − α)[−ln(1 − α)]1/2, one-dimensional Avrami–Erofeev equation f(α) = 1 − α and two-parameter Šesták–Berggren equation f(α) = αm(1 − α)n (m = −0.294, n = 1.428), respectively. Due to the heterogeneity of the thermal decomposition process of (CF)n, the apparent activation energy of the thermal decomposition varied with the extent of conversion. In addition, the final decomposition products of (CF)n were confirmed to be gaseous CF4 and C2F6, and amorphous carbon via Raman spectroscopy and gas chromatography, and the volume ratio of CF4/C2F6 was found to be approximately 12.