MORPHOLOGY-CONTROLLED SYNTHESIS OF OCTAHEDRAL NIXFE1-X@C COMPOSITES DERIVED FROM BIMETALLIC MOFS FOR ENHANCED MICROWAVE ABSORPTION

Carbonaceous materials derived from metal-organic frameworks (MOFs) have attracted significant attention as potential electromagnetic wave absorbers due to their tunable structures, high porosity, and large specific surface areas. In this study, a facile strategy was developed to control the morphology of Ni x Fe 1-x -MOFs by adjusting the Ni/Fe molar ratio in the precursors. Specifically, a near-octahedral Ni x Fe 1-x -MOF structure was successfully synthesized at a Ni/Fe molar ratio of 0.5:0.5. Following pyrolysis at 600°C in a nitrogen atmosphere, porous Ni x Fe 1-x @C composites were obtained. The Ni 0.5 Fe 0.5 @C composite exhibited significantly enhanced microwave absorption performance. At a matching thickness of 1.94 mm, the maximum reflection loss (RL) reached -81.35 dB at 13.8 GHz, with a corresponding effective absorption bandwidth (EAB, RL < -10 dB) of 5.3 GHz (ranging from 11.7 to 17.0 GHz). The superior microwave absorption properties are attributed to the improved impedance matching, multiple polarization relaxations, and conduction losses facilitated by the unique octahedral structure. This research provides a novel approach for the fabrication of high-performance electromagnetic wave absorbing materials through the compositional regulation of bimetallic MOF precursors.