Distinguishing the impact of temperature on iron catalyst during the catalytic-pyrolysis of waste polypropylene

Ning Cai, Sunwen Xia, Haoyu Xiao, Yingquan Chen*, Wei Chen, Haiping Yang, Chunfei Wu, Hanping Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


The catalytic pyrolysis of waste plastics with iron-based catalyst can produce H2 rich gas, liquid oil and carbon nanotube (CNTs) together. While the catalytic pyrolysis mechanism is still unclear, in this study, the catalytic pyrolysis of polypropylene (PP) was explored in depth, and the influence of catalyst and temperature was distinguished. The results indicated that a lower temperature led to the generation of waxes, while a higher temperature promoted the formation of aromatic hydrocarbons when plastic pyrolysis was performed without a catalyst. In addition, a large number of carbon deposits, mainly in the form of spheres, were collected when the temperature was over 800 °C. These carbon spheres originated from the agglomeration of aromatic hydrocarbons. Once catalysts were introduced, a large amount of liquid oil was transferred into carbon deposits at both lower and higher catalytic temperatures, simultaneously, leading to more light gases releasing, like hydrogen. At a lower temperature (≤ 800 °C), it was mainly CNTs while carbon spheres are the main solid product at higher temperatures (> 800 °C). In addition, two different mechanisms of CNTs formation were also concluded that the base-growth model dominated the of generation CNTs at 600 °C whereas the CNTs followed the tip-growth model at 800 °C. The results show that the optimized temperature for the catalytic process should be around 800 o°C where approximately 35 mmol/gplastic hydrogen, 50% hydrogen efficiency and over 320 mg/gplastic carbon nanotubes (CNTs) were obtained.

Original languageEnglish
Number of pages11
JournalProceedings of the Combustion Institute
Early online date06 Jul 2022
Publication statusEarly online date - 06 Jul 2022

Bibliographical note

Funding Information:
The authors wish to express their sincere thanks for the financial support from the National Key Research and Development Program of China ( 2019YFC1904003 ), the National Natural Science Foundation of China ( 51906082 and 51861130362 ), China Postdoctoral Science Foundation ( 2019M662617 ), the Foundation of the State Key Laboratory of Coal Combustion ( FSKLCCB2001 )) and China Scholarship Council ( 202006160077 ). The experiment was also assisted by the Analytical and Testing Center in Huazhong University of Science & Technology ( http://atc.hust.edu.cn , Wuhan 430074 China). This work has been partially funded by the GTCLC-NEG project that has received funding from the European Union's Horizon 2020 research.

Publisher Copyright:
© 2022 Elsevier Ltd. All rights reserved.


  • Carbon nanotubes
  • Catalytic pyrolysis
  • Hydrogen
  • Temperature
  • Waste plastic

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry


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