Realizing the Enhanced Electromagnetic Wave Absorption and Self‐Cleaning Pollution in BaFe ₁₂ O ₁₉ Composite

ABSTRACT With increasing complex requirement in organic pollution environment, the development of actual electromagnetic wave (EMW) absorbers with high EMW absorption performance and self‐cleaning pollution function is becoming a significant challenge. Barium ferrite (BaFe 12 O 19 ), known for its low cost and high production efficiency, is a strong candidate for the development of specialized composites to address this challenge. In this work, we designed and synthesized a novel composite structure in which conductive Cu‐MOF [Cu 3 (HHTP) 2 ] is grown on the surface of Sm‐Ce co‐doped ferrite [Ba 0.94 (SmCe) 0.03 Fe 12 O 19 ], forming an innovative Cu‐MOF‐encapsulated ferrite nanocomposite. The composite exhibits significantly enhanced EMW absorption performance, achieving an effective absorption bandwidth (EAB) of 5.5 GHz at an ultra‐thin thickness of only 1.8 mm. Furthermore, it demonstrates excellent self‐cleaning functionality, capable of degrading 90% of methyl orange (an organic dye) and inhibiting 99% of bacterial growth. These multifunctional properties—superior EMW absorption performance and self‐cleaning capability—are attributed to rare‐earth doping and Cu‐MOF decoration, which induce lattice charge imbalance, a surface “charge pumping” effect, optimized band structure, and Cu 2+ ion release. This study proposes a new strategy for designing multifunctional EMW absorbers, with potential applications in complex environments simultaneously affected by electromagnetic pollution, dye contamination, and microbial hazards.