Nitrogen-doped hollow carbon microcubes modified by in situ catalytic growth of CNTs for broadband microwave absorption

Abstract

The three-dimensional hollow structural design combined with component regulation has been recognized as an effective strategy for achieving lightweight, broadband microwave absorption. Herein, nitrogen-doped hollow carbon microcubes modified with in situ catalytic growth carbon nanotubes (Ni@CNTs/N-HCMs) were successfully fabricated using a salt-template technique followed by a subsequent chemical-catalyzed self-deposition (CCSD) process and a simple water-washing step for template removal. Benefiting from the unique structural features improving the impedance matching and the synergistic effect of multiple components enhancing loss capacity, the microwave absorption performance of the as-obtained Ni@CNTs/N-HCMs composites could be effectively regulated and optimized. Remarkably, with a filling loading of only 3.5 wt%, the optimal reflection loss can reach up to −46.7 dB at 3.7 mm and the maximum effective absorption bandwidth attains 6.1 GHz at 2.0 mm, respectively. Importantly, the salt templates are more economical and environmentally friendly, and the salt templates offer the potential for recycling, facilitating large-scale production of the material. This study provides an innovative path for constructing high-performance functional carbon-based microwave absorption materials.