Fe/Fe3C@N-doped carbon composite materials derived from MOF with improved framework stability for strong microwave absorption

Metal-organic frameworks (MOFs) are widely used in microwave absorption due to their unique microstructure and flexible design of compositions. MOFs and their derivatives are ideal precursors, and MOF-derived porous materials with high porosity, and light weight can be prepared by controlling the pyrolysis and subsequent processing processes. However, an excessively high pyrolysis temperature may lead to the collapse and destruction of the MOF skeleton structure, which seriously affects the effective absorption of electromagnetic waves. In this work, we have prepared a special hexagonal biconical micromorphology Fe-MOF with great tip effect. The stability of the MOF framework was effectively improved by adjusting the synthesis temperature of the MOF. And a good impedance matching between the dielectric and magnetic components was achieved by regulating the degree of carbon graphitization. Among them, the samples synthesized at 180 °C and calcined at 700 °C obtained an effective bandwidth of 5.15 GHz at a matching thickness of 1.7 mm, showing a strong reflection loss high to − 70.8 dB at a thickness of 2.5 mm. We believe that this work provides a new idea for improving the stability of MOF materials and the application of MOF materials in electromagnetic wave absorption.