Hierarchical Heterostructure Ni2P Hollow Carbon Spheres Derived from MOFs for Efficient Electromagnetic Wave Absorption

In this study, a hierarchical heterogeneous structure of Ni2P hollow carbon spheres (Ni2P-HCS) was synthesized through a two-step process involving carbonization and phosphorization of Ni-metal organic framework (Ni-MOF) precursors. During the construction of the Ni2P/C nanostructure, heterointerface recombination and secondary graphitization were observed, which contribute to the modulation of interface polarization. Structural analysis revealed that the Ni2P/C nanoparticles are uniformly dispersed, forming stable porous structured microspheres, thereby leveraging dielectric and magnetic losses. The combination of Ni2P with metal-organic frameworks (MOFs) can optimize impedance matching, enhance effective absorption bandwidth, and consequently improve electromagnetic wave absorption performance. The results show that Ni2P-HCS (Ni2P-HCS700) exhibited superior electromagnetic wave (EMW) absorption characteristics when the carbonization temperature is 700 ℃. It achieves a maximum reflection loss (RL) of −46.7dB at a thickness of 2.9mm and an effective absorption bandwidth (EAB) of 4.8GHz at 1.71mm thickness, almost covering the Ku-band (13.3GHz−18GHz). Radar cross-section (RCS) simulations utilizing CST indicated an optimal RCS reduction value of 41dBm² at theta=0° for Ni2P-HCS700. This work introduces a universal approach to designing high-performance lightweight absorbers derived from MOFs, incorporating transition metal phosphides to form composites for impedance matching control.