Upcycling of waste plastics diverts plastics from landfill,
which
helps in reducing greenhouse gas emissions. Graphitic carbon is an
interesting material with a wide range of applications in electronics,
energy storage, fuel cells, and even as advanced fillers for polymer
composites. It is a very strong and highly conductive material consisting
of weakly bound graphene layers arranged in a hexagonal structure.
There are different ways of synthesizing graphitic carbons, of which
the co-pyrolysis of biomass and plastic wastes is a promising approach
for large-scale production. Highly graphitized carbon with surface
areas in the range of 201 m2/g was produced from the co-pyrolysis
of polyethylene and pinewood at 600 °C. Similarly, porous carbon
having a superior discharge capacity (290 mAh/g) was developed from
the co-pyrolysis of sugar cane and plastic polymers with catalysts.
The addition of plastic wastes including polyethylene and high-density
polyethylene to the pyrolysis of biomass tends to increase the surface
area and improve the discharge capacity of the produced graphitic
carbons. Likewise, temperature plays an important role in enhancing
the carbon content and thereby the quality of the graphitic carbon
during the co-pyrolysis process. The application of metal catalysts
can reduce the graphitization temperature while at the same time improve
the quality of the graphitic carbon by increasing the carbon contents.
This work reports some typical graphitic carbon preparation methods
from the co-pyrolysis of biomass and plastic wastes for the first
time including thermochemical methods, exfoliation methods, template-based
production methods, and salt-based methods. The factors affecting
the graphitic char quality during the conversion processes are reviewed
critically. Moreover, the current state-of-the-art characterization
technologies such as Raman, scanning electron microscopy, high-resolution
transmission electron microscopy, and X-ray photoelectron spectroscopy
are discussed in detail, and finally, an overview on the applications,
scalability, and future trends of graphitic-like carbons is highlighted.