Study of Tire Pyrolysis Oil Model Compound Structure on Carbon Nanomaterial Production

The pyrolysis–catalysis process of waste tires has been reported to produce high value carbon nanomaterials. Tire pyrolysis oils contain a wide range of aliphatic and aromatic compounds. To further investigate the production of carbon nanomaterials from waste tires, model compounds have been investigated with a 10 wt % Ni/Al2O3 catalyst to determine their influence on the production of carbon nanomaterials. The compounds (hexadecane, decane, styrene, naphthalene, and phenanthrene) were chosen to represent typical aliphatic and aromatic compounds detected in tire pyrolysis oils. It has been found that the aromatic compounds dominated solid nanocarbon production compared with aliphatic compounds, especially for the production of highly graphitic filamentous carbon. The filamentous carbon produced from aliphatic compounds was in the range from 27.06 to 77.97 mg g–1 of feedstock equivalent carbon, and the filamentous carbon produced from aromatic compounds ranged from 104.53 to 174.19 mg g–1 of feedstock equivalent carbon. The filamentous carbon was further characterized by thermogravimetric analysis, electron microscopy, and Raman spectroscopy, which confirmed that the filamentous carbon was composed of both hollow carbon nanotubes and solid carbon nanofilaments. The quality of the produced filamentous carbon was shown by Raman spectroscopy analysis to be very similar to commercial filamentous carbon.