Constructing TCNFs/MXene/TiO2 microspheres with wrinkled surface for excellent electromagnetic wave absorption

Constructing a wrinkled surface can increase the external surface area and provide a multi-directional reflective surface, so as to increase the interface polarization sites and produce multiple reflection scattering. It is considered to be one of the feasible means to improve the microwave absorption performance of materials. In this paper, the TPNFs/MXene composite microspheres with 3D wrinkled structure have been obtained by combining the two elementary materials of 1D TPNFs and 2D MXene nanosheets with the help of ultrasonic spray drying self-assembly technology. After calcination at high temperature, TPNFs/MXene microspheres are transformed into TCNFs/MXene/TiO 2 composite microspheres. TCNFs/MXene/TiO 2 composite microspheres also have a wrinkled surface, providing interfacial polarization sites and reflective surfaces. TCNFs are interspersed in the MXene nanosheets to play the role of structural reinforcement and charge conduction. TiO 2 nanoparticles are uniformly distributed on the surface of MXene, forming multiple heterogeneous interfaces with TCNFs and MXene. Under the synergistic effect of composition and structure, TCNFs/MXene/TiO 2 composite microspheres exhibit excellent microwave absorption performance. At the matching thickness of 3.5 mm, the minimum reflection loss is − 57.01 dB @ 7.2 GHz with an effective bandwidth of 2.5 GHz, covering the low-frequency region of 6.1–8.6 GHz. Adjusting the thickness to 1.8 mm, the effective bandwidth reaches the maximum of 4.7 GHz (13.3–18 GHz). This research provides an effective way for the assembly of low-dimensional nanomaterials to prepare 3D microwave absorbers with wrinkled surface. ● TCNFs/MXene/TiO 2 microsphere with wrinkled surface is prepared. ● The precursor is synthesized by ultrasonic spray drying self-assembly method. ● 1D TPNFs and 2D MXene nanosheets are used as structural units. ● The influence of TPNFs:MXene ratio on structure and property are investigated. ● TCNFs/MXene/TiO 2 exhibits excellent microwave attenuation performance.