Construction of secondary heterojunction interface between 2D NiCo-LDH and MOF-derived 0D Co@NC for enhanced electromagnetic response

Abstract

The development of hierarchical heterostructures to enhance the interfacial interactions between substrates and ligands is recognized as an effective approach for optimizing electromagnetic wave (EMW) absorption performance. Nonetheless, the advancement of novel EMW absorbers with ultrathin matching thickness (d < 1 mm), robust reflection loss (RL ≤ -50 dB), and a broad effective absorption bandwidth (EAB, RL ≤ -10 dB) continues to present a formidable challenge. In this work, we have manufactured Co@NC/NiCo-LDH absorbers featuring hierarchical hetero-interfacial structures. This was accomplished using a straightforward hydrothermal method that induced the in-situ growth of 2D NiCo-LDH nanosheet ligands on the surface of 0D Co@NC heterostructured substrates. Both 0D Co@NC heterostructures and 2D NiCo-LDH nanosheets are composed of small nanoparticles, creating many homogeneous and heterogeneous interfaces, and substantially augmenting interfacial polarization loss. The Co@NC/NiCo-LDH hierarchical hetero-interfacial structure demonstrates strong dielectric loss (interfacial polarization, conductive loss, dipolar polarization), magnetic loss (natural resonance and switched resonance), and excellent impedance matching. As a result, the Co@NC/NiCo-LDH heterostructure displays excellent EMW absorption characteristics with reflection loss (RL) values of -55.78 dB and -60.53 dB at matching thicknesses of 0.97 mm and 1.45 mm, respectively. The EAB value can reach 4.36 GHz. Furthermore, the Co@NC/NiCo-LDH absorber demonstrates outstanding radar wave attenuation performance through radar cross-section simulation (RCS). It achieves a maximum RCS reduction value of 30.96 dB m2. This research offers valuable insights into the EMW absorption mechanism of hierarchical hetero-interfacial structures, contributing to a deeper understanding of the design and utilization of multilevel heterostructures.