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

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.