Simultaneous manipulation of constituent and structure toward MOFs-derived hollow Co3O4/Co/NC@MXene microspheres via pyrolysis strategy for high-performance microwave absorption

The development of microwave absorbing materials with high performance is one of the effective strategies to solve the increasingly serious electromagnetic pollution problem, and has received the attention of researchers. Herein, the structure and composition manipulation of Ti3C2Tx MXene and MOFs derivatives are investigated. It is found that the TiO2 produced by oxidation of Ti3C2Tx MXene, as a low dielectric material, can effectively solve the impedance mismatch caused by the high conductivity of Ti3C2Tx MXene. Additionally, MOFs derivatives with excellent dielectric-magnetic properties are often obtained by high temperature pyrolysis, which also aids in the oxidation of Ti3C2Tx MXene. Here, we successfully synthesized ZIF-67 nanoparticles on the surface of a three-dimensional spherical skeleton supported by Ti3C2TX MXene nanosheets through template method and electrostatic self-assembly, and obtained Co3O4/Co/NC@MXene microspheres with an obvious hollow structure after one-step pyrolysis. This magnetic carbon heterostructure could effectively optimize the impedance matching and achieve efficient microwave absorption. The HCCM-800 sample had a minimum reflection loss value of −71.60 dB with thickness of 2.25 mm and a maximum effective absorption bandwidth achieved 5.14 GHz at 1.85 mm. Meanwhile, the radar cross section (RCS) simulation revealed that the HCCM-800 sample's RCS reduction value could reach 20.2 dBm2 at 0° incidence angle. It is believed that this research will pave the way for further vigorous development in the field of microwave absorption.