TiO2 Nanosheets/Ti3C2Tx MXene 2D/2D Composites for Excellent Microwave Absorption

Ti3C2Tx MXene is a potential microwave absorption material due to its unique physical and chemical properties. However, the impedance mismatch of MXene results in low microwave absorption. In this work, 2D/2D MXene@TiO2 composites were synthesized via a simple hydrothermal oxidation method, TiO2 is derived in situ from MXene without adding any additional Ti precursors. TiO2 with low permittivity can effectively regulate the impedance matching and enhance loss mechanisms. The MXene@TiO2-6 h composite shows a reflection loss (RL) of −58.3 dB at 11.36 GHz with a thickness of 1.75 mm, and the maximum effective absorption bandwidth (EAB) is 4.08 GHz (13.92–18 GHz) at 1.26 mm. Furthermore, the 2D/2D composite can obtain efficient microwave absorption at different frequencies by adjusting the thickness; RL can reach −39.1 dB at 5.04 GHz with a thickness of 3.5 mm. The radar cross section (RCS) of MXene@TiO2-6 h is lower than −19 dB m2 at −60–60°, and the minimum RCS is −56 dB m2 at 15°. This work provides a valuable experience in developing microwave absorption materials.