Single step microwaves assisted catalytic conversion of plastic waste into valuable fuel and carbon nanotubes

The deconstruction of plastic waste into hydrogen, carbonaceous materials and hydrocarbons is an attractive way of meeting the global energy demand. This paper presents single-step microwave pyrolysis of high-density plastic waste using different catalysts to produce hydrogen and carbon nanotubes (CNTs). For catalytic pyrolysis, NiFe2O4, Al2O3, and Fe2O3 catalysts were prepared through a facile sol-gel method. The highest hydrogen yield was recorded with NiFe2O4 catalyst, which is about 57 mmol.g−1. The hydrogen production efficiency was about 93 wt.%. In comparison to polypropylene (PP) and high-density polyethylene (HDPE), the polystyrenes (PS) produced the highest yield of solid carbon (73 wt.%) with NiFe2O4 catalyst. The produced CNTs were characterized through XRD, TEM, SEM, TGA and RAMAN spectroscopy. The NiFe2O4 catalyst produced relatively pure and well-structured CNTs as compared to Al2O3 and Fe2O3 catalysts.