Defect Dipole-Induced HfO2-Coated Ti3C2Tx MXene/Nickel Ferrite Nanocomposites for Enhanced Microwave Absorption

This work reports for the first time the synthesis of a HfO2-coated Ti3C2Tx MXene sandwich-like nanostructure (MXHf) using a simple hydrothermal method and their excellent microwave absorption property in combination with nickel ferrite and epoxy matrix. The nanocomposites of 2, 3, and 4 mm thick samples were tested for microwave absorption in the X-band, and a minimum reflection loss (RLmin) of -20.9 dB with EAB (effective absorption bandwidth) of 2.32 GHz was achieved for the 3 mm thick sample. Its superior performance results from the strong dielectric polarization of defect dipole in the MXene structure, the high number of oxygen vacancies brought about by HfO2 nanoparticles, rich micro-interfaces in the sandwich-like HfO2- Ti3C2Tx-HfO2 structure, and impedance matching by NiFe2O4. A probable mechanism of absorption is proposed. Hence, HfO2/Ti3C2Tx/NiFe2O4 nanocomposites possess essential properties for real-time application in the defense and telecommunication industries.

Automated summary

This work demonstrates the synthesis of HfO2-coated Ti3C2Tx MXene sandwich-like nanostructures and their excellent microwave absorption properties when combined with nickel ferrite and epoxy matrix. The results show strong absorption at the X-band, with a minimum reflection loss of -20.9 dB and an effective absorption bandwidth of 2.32 GHz for the 3 mm thick sample. The superior performance is attributed to dielectric polarization, oxygen vacancies, micro-interfaces, and impedance matching. The HfO2/Ti3C2Tx/NiFe2O4 nanocomposites have potential applications in defense and telecommunication industries.