Optimized Impedance Matching with N,S-Doped Graphene Modified Metal–Organic Framework Derived Fe/Fe2O3/C Composite toward High-Efficiency Microwave Attenuation

Metal–organic frameworks (MOFs)-derived compounds exhibit tremendous potential for applications in the field of microwave absorption, attributed to their unique structural characteristics, high specific surface area, and tunable magnetic and dielectric properties. However, their practical application in the microwave absorption field is limited by poor impedance matching. To address this issue, we successfully synthesized a composite microwave-absorbing material, labeled as Fe/Fe2O3/C/N,SGPE, by introducing heteroatom (N and S) codoped graphene (labeled as N,S-GPE) into an Fe/Fe2O3/C MOF derivative and employing a solvothermal method followed by subsequent pyrolysis. The introduction of N and S codoped graphene introduces defects and disordered structures, thereby enhancing interface and dipolar polarization processes, which in turn improve the dielectric properties and optimize impedance matching. The experimental results demonstrate that when the addition amount of N,S-GPE is 0.15 g, the material exhibits a maximum reflection loss of -62.8 dB at 7.6 GHz with a thickness of 3.09 mm, capable of absorbing over 99.9999% of microwaves. Consequently, this composite stands out as a promising candidate for high-efficiency microwave absorbers.