Integrating multiple interface polarization in hierarchical hollow nanospheres for superior electromagnetic wave absorption and the simulation of ultrastructure

In the face of increasingly complex electromagnetic (EM) pollution, heterogeneous interface engineering is an effective strategy to promote EM response. The enrichment of heterogeneous interfaces can be achieved by constructing hierarchical hollow structures. In this study, waxberry-like hierarchical hollow carbon nanospheres (HHMC) embedded with ultrafine Mo 2 C nanoparticles (NPs) are synthesized by carbonization of phenolic resin microspheres using ammonium molybdate as a molybdenum source and SiO 2 as a pore-forming agent. Among them, the good dispersion of Mo 2 C NPs forms a large number of nanoscale heterogeneous interfaces, which strengthens the polarization relaxation process. Concurrently, the hierarchical hollow structure optimizes the impedance matching with the air medium. Thanks to these properties, the prepared HHMCs exhibit remarkable EM attenuation capacity with a minimum reflection loss (RL) of -59.6 dB and an effective absorption bandwidth (EAB) up to 4.8 GHz. Furthermore, macroscopic three-dimensional (3D) metasurface simulations reveal its ultra-broadband absorption characteristics, which extend from 10.4 GHz (7.6-18 GHz) to 14.1 GHz (3.9-18 GHz) as the thickness increases from 1.4 mm to 3 mm. This result provides fundamental guidance for efficient EM energy attenuation through heterogeneous interface engineering.