Copper Single Atoms on N-Doped Hollow Nanocubes for Efficient Electromagnetic Wave Attenuation

Rational design of unique nanostructures and suitable compositions is essential for highly-efficient electromagnetic wave (EMW) absorbing materials. Metal single-atoms (M-SAs) anchored on hollow-structured carbon-based materials have emerged as promising absorbers owing to their unique nanostructures and tunable electronic configurations. However, the synergistic coupling mechanism between hollow structure and M-SAs still remains poorly understood. Herein, an in situ vapor evaporation strategy is developed to anchor copper single-atoms on N-doped hollow carbon nanocubes (Cu-SAs/NHCC) for enhanced EMW absorption. Theoretical calculations indicate that the incorporation of Cu-SAs induces the charge redistribution and higher electrical conductivity, leading to stronger dielectric loss. Simulation results reveal that the hollow structure is beneficial for optimizing inadequately matched impedance. Consequently, the synergistic interaction between M-SAs and hollow nanostructure significantly improves EMW absorbing capability, which can be verified by the experimental results. The Cu-SAs/NHCC exhibits a minimum reflection loss (RL_min) of -51.54 dB and an effective absorption bandwidth (EAB) of 4.34 GHz at a filler loading of 11 wt.%. Furthermore, the film consists of Cu-SAs/NHCC and aramid nanofibers, displays exceptional flexibility, stability, mechanical, and thermal insulating performance, highlighting potential multifunctional applications of Cu-SAs/NHCC. This work provides a viable strategy for designing high-performance EMW absorbers based on M-SAs with tailored nanostructures.