Preparation of synthetic graphite from waste PET plastic

[Display omitted] •From waste PET plastic, graphite was prepared through a facile method.•The PET-derived graphite exhibited a high degree of graphitization.•Graphene sheets were successfully obtained by exfoliating the PET-derived graphite. The development of new technologies for converting waste plastics into value-added products is attracting widespread attention because of the global plastic waste crisis. In this study, we present a novel route for the upcycling of waste plastics, wherein synthetic graphite is prepared from a waste polyethylene-terephthalate (PET) bottle through a facile and scalable method. PET was successfully converted to graphite via a synthetic method of pyrolysis at 900 °C followed by boron-assisted catalytic graphitization at 2400 °C. This technique overcame the intrinsic non-graphitizable property of PET and yielded graphite showing high crystallinity with the maximum crystallite size of 20.9 nm in Lc and the d(002) spacing of 3.373 Å. In particular, it showed a much higher degree of graphitization (80.6%) than that (68.9%) derived from a well-known AR mesophase pitch (Mitsubishi). In addition, via a microwave-assisted liquid-phase exfoliation, the PET-derived graphite was successfully exfoliated as graphene sheets with the average lateral size of 410 nm. We expect that our work can guide the innovative upcycling of waste plastics to invaluable synthetic graphite, which has many potential applications such as anode materials in secondary batteries and fillers for carbon composites, and may serve as an alternative source for graphene production.