Anion-substitution interfacial engineering to construct C@MoS hierarchical nanocomposites for broadband electromagnetic wave absorption.

Developing an effective strategy to regulate the interfacial properties of hierarchical structure is of great significance for preparation of high-performance electromagnetic wave absorption (EMA) materials. Ion-substitution can change intrinsic structure and properties of a materials, but its effect on the interfacial properties of hierarchical structure remained to be explored. Herein, we first constructed a C@MoS hierarchical structure via simple hydrothermal reaction, then used the ion-substitution strategy to replace the S atoms in MoS with O, F and Se, and finally obtained anion-substituted hierarchical structure (C@X-MoS, X = O, F, Se). The results show that ion-substitution destroys the MoS crystal structure and realizes tunable dielectric properties of C@MoS, which leads to further enhancement of overall interfacial polarization. After optimization, the absorption strength and width of C@O-MoS has been significantly improved. The minimum reflection loss (RL) reaches -62.17 dB, and the maximum effective absorption bandwidth (EAB) is 7.0 GHz. The simulation results show the obtained absorbent can greatly reduce the radar cross section of target, indicating it has broad application potential. Therefore, this work provides a novel method for regulation of EMA performance of hierarchical structure and preparation of high-performance absorbents.