Confined Tuning Hierarchical Core–Shell Architectures of Multi-Walled Carbon Nanotubes Wrapped by MnO2 Sheets with High-Performance Microwave Absorption

Abstract

Hierarchical core–shell architectures with multi-walled carbon nanotubes as core and MnO2 sheets shaped in an array mode as shell (MWCNTs@MnO2) were successfully synthesized via a simple wet chemical method. X-ray diffraction patterns and X-ray photoelectron spectroscopy analysis revealed that the composites were successfully prepared. Morphological characterizations were made by scanning electron microscopy and transmission electron microscopy. Vector network analyzer was employed to investigate the electromagnetic parameters of the composites. A possible attenuation mechanism was discussed, and the high-performance microwave absorption properties were attributed to the porous microstructure, polarization effect, dielectric loss and the synergistic action between MWCNTs and [Formula: see text]-MnO2. A minimum reflection loss (RL) of [Formula: see text]50.6[Formula: see text]dB was achieved at a thickness of 1.4[Formula: see text]mm, and an effective absorption bandwidth ([Formula: see text][Formula: see text]dB) covered 4.2[Formula: see text]GHz (from 13.8[Formula: see text]GHz to 18[Formula: see text]GHz) at a thickness of 1.3[Formula: see text]mm. Therefore, these results suggested that the MWCNTs@[Formula: see text]-MnO2 composites can be an excellent candidate for microwave absorption materials.