Identify the impact of pyrolysis temperature on preparation of carbon nanotubes by catalytic reforming polypropylene
Ning Cai, Qingyu Liu, Xiaoqiang Li, Shujiang Li, Haiping Yang, Hanping Chen
Abstract
Catalytic reforming offers a promising method for converting waste plastics into valuable products such as carbon nanotubes (CNTs). The composition of the carbon source plays a crucial role in determining the growth of CNTs because pyrolysis temperature exerts a significant influence on volatilisation. This study investigated the impact of pyrolysis temperature on the formation of CNTs in the presence of an Fe/Al 2 O 3 catalyst. A pyrolysis temperature of 500 ℃, generated a liquid product containing a high concentration of long-chain waxy hydrocarbons, while the gaseous products were dominated by C 3 H 6 (47 vol%) and C 2 H 6 (20 vol%). Increasing the pyrolysis temperature facilitated the formation of CH 4 and aromatic hydrocarbons at the expense of the waxy components. Following catalysis, carbon deposits of > 30 wt% (comprising approximately 80 % CNTs) were obtained at 500 ℃, compared to 20 wt% (with CNTs comprising 60 %) at 900 ℃. In summary, the results suggest that small molecular hydrocarbons, including C 3 H 6 and waxy components, promote CNT formation, whereas aromatic hydrocarbons contribute to the formation of amorphous carbon or coke.