Abstract 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 A. 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.

中文翻译：

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用废PET塑料制备合成石墨

摘要 由于全球塑料垃圾危机，废塑料转化为高附加值产品的新技术的开发正受到广泛关注。在这项研究中，我们提出了一种废塑料升级回收的新途径，其中合成石墨是通过一种简便且可扩展的方法从废聚对苯二甲酸乙二醇酯 (PET) 瓶中制备的。通过在 900 °C 下热解，然后在 2400 °C 下硼辅助催化石墨化的合成方法，PET 成功转化为石墨。该技术克服了 PET 固有的不可石墨化特性，产生的石墨具有高结晶度，Lc 中的最大微晶尺寸为 20.9 nm，d(002) 间距为 3.373 A。特别是，它表现出更高的石墨化程度（ 80.6%) 比 (68. 9%) 源自众所周知的 AR 中间相沥青（三菱）。此外，通过微波辅助液相剥离，PET 衍生的石墨成功剥离为平均横向尺寸为 410 nm 的石墨烯片。我们希望我们的工作可以引导废塑料的创新升级回收为无价的合成石墨，其具有许多潜在的应用，例如二次电池中的负极材料和碳复合材料的填料，并可作为石墨烯生产的替代来源。