Upcycling Plastic Waste into Graphitic Carbons

A. Gharpure, M. Kowalik, A. van Duin, R. Rajagopalan, C. Leon y Leon, E. Bazilevskaya, and R. Vander Wal
Penn State,
United States

Keywords: Graphitic carbons, waste plastic, carbon yield, characterization


The future of renewable energy hinges on large scale effective energy storage and graphitic carbon is integral to Li ion batteries for grid related applications and electric vehicles. With the decline in the supply of traditional precursors such as high-quality coal tar, obtaining carbons from plastic waste can provide an environmentally friendly alternative to support renewable energy storage. Barriers to upcycling waste plastic include low yield and non-graphitizable nanostructure of carbons derived from plastic. We demonstrate a novel solution using Graphene Oxide (GO) as a templating agent to increase yield and graphic quality of carbons obtained from plastic waste. GO is used to provide the oxygen required for polymer stabilization while the sp2 framework serves as a template guiding the reconstruction of the polymer chains into a graphitic material. Notably as a 2D material the graphene oxide sp2 framework has the proper form to promote graphitic lamellae and crystallite formation. Compared to “traditional” catalysts such as transition metals or clays, no purification or catalyst removal is required as the transformed GO additive will have the same composition as final graphite. Aromatic growth on and around the templating agent as a result of chemical bonding and sp2 interactions can promote more ordered carbons with graphitic nanostructure. Composites with various grades of GO show that oxygen content and lateral size are the dominant factors in GO-plastic interactions. GO increased the carbon yield dramatically and the graphitic quality of the composites has been analyzed using XRD, HRTEM, SAED and Raman Spectroscopy. Molecular dynamic simulations provide supporting evidence. This work will create a new path for graphite manufacture netting energy savings by lower process temperature and environmental benefits by reduced process CO2. Demonstrated production of high value carbons from waste plastic will boost recycling and enable other related uses for carbon materials from plastic waste.