Short carbon nanorod-grafted N-doped carbon nanocages derived from LDH/MOFs for efficient electromagnetic wave absorption

The systematic design of morphology and structure plays a significant role in enhancing the physicochemical properties of functional materials. In this work, short carbon nanorod-grafted magnetic N-doped carbon nanocage (FeCoNi@NC) was prepared using FeCoNi layered double hydroxide (LDH)/metal organic frameworks (MOFs) as precursor. Herein, a multi-level hollow nanocage was synthesized by hydrothermal method, in which nanorods were formed on the surface of the hierarchical structure, and after annealing, an N-doped hollow nanocage with short carbon nanorod-grafted was formed. Due to its unique hollow and hierarchical interfaces, the optimal FeCoNi@NC exhibits highly efficient electromagnetic wave absorption (EWA). At 14.32 GHz, the minimum reflection loss ( RL min ) reach -54.4 dB, while the effective absorption bandwidth (EAB) is over a wide range of 5.28 GHz, corresponding to a thickness of 1.5 mm. The outstanding ability to absorb electromagnetic waves is due to the hierarchical and hollow characteristics, which increase dielectric and conductive losses, while also optimizing impedance matching. The study presents a highly effective approach to fabricate hierarchical and hollow nanostructures with short nanorods, aiming to enhance the efficiency of EWA.