3D Porous Graphene with Atomic Fe Coordinated by Pyrrole‐N Dopants for Efficient Electromagnetic Wave Absorption with Low Filler Loading and Thin Thickness

Achieving effective electromagnetic wave (EMW) absorption performance with less than 2 mm remains a significant challenge in developing EMW absorption materials. Herein, Fe atoms embedded into NH₃-treated 3D porous graphene (3DPG-NH₃-Fe) are synthesized via a simple method of Fe ion impregnation for efficient EMW absorption. The NH₃-treated process enables the formation of specific pyrrole-N dopants in 3DPG, which provide the anchoring sites for complexing Fe atoms to construct FeN_x moieties. Compared to pristine 3DPG, 3DPG-NH₃-Fe exhibits remarkable EMW absorption characteristics, achieving a minimum reflection loss (RL) of -56.35 dB and an effective absorption bandwidth (EAB) of 4.45 GHz at a low filler loading of 3 wt.% and a thin thickness of 1.4 mm, exceeding the most of reported graphene-based EMW absorption materials. The outstanding performance is critically attributed to the incorporation of the specific Fe coordinated by pyrrole-N dopants with a strong orbital hybridization of N-p_y and Fe-3d_x2-y2 into graphene, which not only produces additional dipoles but also generates high spin Fe atomic magnetic moment, thus enhancing both dielectric loss and magnetic loss for EMW. This work demonstrates a new route for modulating the electromagnetic characteristics of graphene to achieve low filler loading and thin thickness of EMW absorption.