Upcycling Waste Polypropylene into Graphene Flakes on Organically Modified Montmorillonite

Recently, upcycling waste plastics into high-value-added carbon nanomaterials has attracted much attention; however, few studies have focused on the conversion of waste plastics into graphene with high yield. Herein, we report a simple novel method to synthesize graphene flakes (GFs) with high yield through catalytic carbonization of waste polypropylene (PP) using organically modified montmorillonite (OMMT) as degradation catalyst and template at 700 C. The yield, morphology, microstructure, phase structure, thermal stability, and surface element composition of GFs were investigated. In addition, it was found that OMMT not only promoted the degradation of waste PP into light hydrocarbons and aromatics but also acted as template and catalyzed carbonization of the light hydrocarbons and aromatics into GFs. At last, a possible mechanism for the formation of GFs was put forward. This simple approach provides a novel way to effectively prepare high-value-added GFs using waste plastics as carbon sources.