Morphology engineering of MIL-88A-derived 0D/1D/2D nanocomposites toward wideband microwave absorption

Abstract

Metal-organic frameworks (MOFs) have been widely applied in the field of electromagnetic wave absorption (EMWA) on account of unique morphology, simple fabrication, and ultra-high porosity. Nevertheless, the facile method of protecting its structure from being destroyed remains challenging. Herein, we proposed a hydrothermal method combined with a carbonization strategy to construct the 0D/1D/2D Fe₃C@NC@Mo₂C/Fe₃C composites. Owing to the incorporation of polydopamine (PDA), the carbon shell formed during high-temperature carbonization effectively protected the original MIL-88A rod-like structure, and the 2D Mo₂C nano-sheets and 1D Fe₃C nanoparticles were coated on the surface of 1D Fe₃C nanorods. With the increase in carbonization temperature, the EMWA properties of the composites presented a trend of first increasing and then decreasing. Impressively, the composites (at 750 °C) exhibited praiseworthy EMWA performances with a minimum reflection loss value of −43.70 dB at 8.00 GHz, alongside a maximum effective absorption bandwidth of 6.08 GHz (11.20–17.28 GHz). Density functional theory calculations confirmed the distinctive charge distribution resulting from the heterointerface, which is beneficial to the polarization loss and conductive loss. As a result, the outstanding EMWA performance was credited to the distinctive hierarchical structure, appropriate impedance matching, numerous heterogeneous interfaces, and magnetic loss. Moreover, Radar cross-section calculations indicated that the composites have tremendous potential for practical application. Thus, this work may pave new avenues for designing high-performance and structure-controllable absorbing materials.