In situ growth of globular MnO2 nanoflowers inside hierarchical porous mangosteen shells-derived carbon for efficient electromagnetic wave absorber

Abstract

Developing electromagnetic wave (EMW) absorbing materials with reasonable structure and composition is of great significance. In this work, the porous mangosteen shells-derived carbon embedded with globular MnO2 nanoflowers (MnO2@PMSC) were fabricated via two-step carbonization and subsequent hydrothermal synthesis. The biomass-based carbon with highly opened hierarchical porous structures provides abundant in-situ growth points for globular MnO2 nanoflowers, ensuring that they could nucleate in situ and grow inside the carbon walls. It is worth noting that the EMW absorption properties of the absorber can be efficiently enhanced by tuning the contents of globular MnO2 nanoflowers. The as-synthesized optimal sample (MnO2@PMSC-2) exhibits superior EMW absorption performances with the minimum reflection loss (RLmin) value of −54.61 dB and wide effective absorption bandwidth (EAB) of 4.10 GHz at 1.80 mm. The excellent EMW absorption performance is attributed to the multiple reflection and scattering caused by the hierarchical porous structures of the biomass carbon and the flower–like structure of MnO2, strong polarization effects between MnO2 and carbon walls, as well as the good impedance matching condition achieved by the strong synergy between the two components. These results indicated that MnO2@PMSC-2 is a potential electromagnetic wave absorber.