Hollow MoC/NC sphere for electromagnetic wave attenuation: direct observation of interfacial polarization on nanoscale hetero-interfaces

Carbon-based composites with hetero-interfaces is a group of promising electromagnetic wave absorbing materials (EWAMs) for their excellent dielectric loss. For developing this kind of EWAMs, in situ construction of hetero-interfaces and revealing its attenuation mechanism are of great importance, but remain challenges. Herein, a MoC-incorporated N-doped carbon hollow sphere (H-MoC/NC) with uniformly distributed nanoscale MoC/NC hetero-interfaces was precisely synthesized for evaluating the interfacial polarization in electromagnetic wave attenuation. The Mo defects in MoC not only contributed to the impedance matching through the hollow shell, but also accelerated the charge transfers, displaying an enhanced interfacial charge polarization. More importantly, this polarized charge distribution on the MoC(-)/carbon(+) interface was observed for the first time directly through the hologram at a nanometer scale. The atomic-level understanding of interfacial polarization in the electromagnetic attenuation process will greatly promote the development of designing and synthesizing non-magnetic carbon-based EWAMs.