Interface engineering to regulate hollow one-dimensional N-doped Carbon@ZnO nanocomposite for boosting electromagnetic wave absorption

Hollow composite structure has attracted much attention due to its great design space for adjusting impedance matching and enhancing interfacial polarization. Heterogeneous interface as well as improve the polarization relaxation and enhance the dielectric loss ability of material. However, the precise control of heterogeneous interface and hollow structure is a complex issue, which hiders the development of hollow composite structure for practical application. Herein, a mild sacrificial template method is proposed to construct a hollow nanocomposite comprised of N-doped carbon and ZnO (ZnO@HNCR), where self-assembled nanostructure (9,10-dibromoanthracene, DBA), polydopamine (PDA) and ZIF-8 were used as a sacrificial template, conductive scaffold and the ZnO precursor, respectively. During the calcination treatment, ZIF-8 and PDA were in situ converted into ZnO and N-doped carbon. In addition, self-assembled nanostructure sublimated away, leaving hollow structure behind, which overcomes the shortcoming of using corrosive agents. The large specific surface area and unique hollow structure optimize the impedance matching, and the abundant heterogeneous interfaces between HNCR and ZnO improve interfacial polarization. By virtue of joint efforts of conduction loss, multiple scattering and polarization relaxation, ZnO@HNCR exhibits outstanding performance, including minimum reflection loss value (RLmin) of − 57.4 dB at 2.6 mm and effective absorption bandwidth (EAB) of 6.04 GHz at 2.2 mm. This work proposes a feasible method to synthesize hollow heterogeneous electromagnetic absorbent.