Construction of Highly Efficient 3D/2D MnO2/g-C3N4 Nanocomposite in the Epoxidation of Styrene with TBHP

MnO2/g-C3N4 nanocomposites were facilely synthesized by calcining the mixture of bulk g-C3N4 and MnO2 precursors. The effects of the morphology of MnO2 precursors and the mass ratio of MnO2 to g-C3N4 on the micromorphology, chemical compositions, and catalytic properties of MnO2 NP/g-C3N4 nanocomposites were studied. It was found that the 3D polyhedral morphology and multiphase polycrystalline structure of MnO2 were propitious to generate the strong interaction between MnO2 and g-C3N4, which led to the enhanced concentrations of surface low-valence Mn species, oxygen vacancies, and graphitic N species. Meanwhile, when the mass ratio of MnO2 NP to g-C3N4 was 8/100, the interface of 8MnO2NP/UCN possessed the optimum synergistic effect of MnO2 NP and g-C3N4, contributing to the superior catalytic performance of 8MnO2NP/UCN with much higher yield of styrene oxide compared to other counterparts.