Synthesis of two-dimensional holey MnO2/graphene oxide nanosheets with high catalytic performance for the glycolysis of poly (ethylene terephthalate)

Two-dimensional (2D) materials have been extensively studied as promising heterogeneous catalysts because of their high surface area, outstanding mechanical strength, and excellent chemical and thermal stability. Herein, we report an efficient and simple two-step strategy for the synthesis of 2D holey and ultrathin MnO2/graphene oxide nanosheets. As a 2D nanoporous support, holey graphene oxide (HGO) nanosheets are prepared by an oxidative etching method. The uniform and conformal deposition of MnO2 onto the HGO surface is performed by a solution-based self-limiting redox reaction, resulting in nanoporous MnO2/HGO nanosheets with a high surface area. The resulting MnO2/HGO shows outstanding catalytic performance for the glycolysis of polyethylene terephthalate (PET). A high conversion of PET (100%) and a high yield of a bis(hydroxyethyl) terephthalate (BHET) are achieved within a short reaction time of 10 min at a reaction temperature of 200 degrees C. Furthermore, the MnO2/HGO catalyst shows excellent recyclability for the glycolysis of PET; a BHET yield of 100% is obtained after 5 cycles.