Qingze Xue, Ping Wang, Xiaopeng An, Han‐Wen Cheng, Yan Wang, Renchao Che
ABSTRACT Although metal–organic framework (MOF) derivatives are promising materials for electromagnetic wave (EMW) absorption, their inherent physical characteristics restrict loss capabilities. This study overcame this constraint via a dual strategy involving precisely constructed heterointerfaces and the modulation of defects. Controlled selenization yielded an atomically continuous heterojunction (CoSe 2 /Cu 2 Se), stabilizing electron accumulation zones critical to interfacial polarization. Concurrently, N/Se co‐doping into the derived carbon framework significantly modified its electronic configuration, increased the density of states near the Fermi level, and generated abundant defect‐induced dipoles. A hollow architecture, stabilized by interfacial interactions, optimized impedance matching via balanced permittivity and permeability while extending the propagation path of EMWs. Micromagnetic simulations confirmed enhanced magnetic anisotropy and domain wall displacement in the hollow structure, resulting in improved magnetic loss. The optimized absorber achieved an effective absorption bandwidth of 7.6 GHz, a minimum reflection loss of −57.2 dB at 2.1 mm, and a radar cross‐section reduction of 29.9 dB·m 2 . This work illustrates a rational design strategy for MOF‐derived absorbers via heterointerface engineering, vacancy tailoring, and structural optimization, offering a feasible route toward high‐performance EMW absorption for practical applications.