Enhancing carbon nanotubes production from pyrolysis–catalysis of plastic waste through monolithic heating

ABSTRACT In this study, we developed a novel monolithic heating method by utilizing electromagnetic induction to enhance carbon nanotube (CNT) production from plastic waste via pyrolysis–catalysis. Metal porous catalysts, including iron (Fe), nickel (Ni) and Fe–Ni alloy, enabled rapid volumetric heating, improved catalytic efficiency and reduced energy consumption compared with conventional methods. The porous Fe catalyst demonstrated superior CNT yield, while Ni provided the highest hydrogen (H2) production. We achieved carbon-recovery efficiencies of 86%, 84% and 82% for low-density polyethylene, high-density polyethylene and polypropylene, respectively, by using the Fe catalyst. Our economic analysis indicated that CNT production from waste polyethylene and waste polypropylene is feasible, with break-even selling prices of $4.02 and $4.87 kg−1, respectively. Our work supports the development of a circular economy by enabling the efficient conversion of plastic waste into valuable CNTs and H2 via pyrolysis–catalysis.