High-Efficiency\nElectromagnetic Wave Absorption of\nCobalt-Decorated NH₂‑UIO-66-Derived Porous ZrO₂/C

Abstract

Broadband\nabsorbers derived from metal–organic frameworks\nare highly desirable in the electromagnetic (EM) wave absorption field.\nHerein, a strategy for cobalt-decorated porous ZrO₂/C hybrid\noctahedrons by pyrolysis of Co­(NO₃)₂-impregnated\nNH₂-UIO-66 was developed. The hybridization of Co nanoparticles\nwith ZrO₂/C results in remarkable EM wave absorption performance\nwith a minimum reflection loss (RL) of −57.2 dB at 15.8 GHz,\ncorresponding to a matching thickness of 3.3 mm. The maximum effective\nabsorption bandwidth (RL ≤ −10 dB) reaches 11.9 GHz\n(6.1–18 GHz), covering 74.4% of the whole measured bandwidth.\nThe textural properties of nanocomposites have been thoroughly characterized\nby powder X-ray diffraction, electron microscopy, X-ray photoelectron\nspectroscopy, and nitrogen adsorption–desorption isotherms.\nThe corresponding results show that the face-centered cubic-phased\n∼50 nm Co nanoparticles are evenly distributed on the surface\nof porous ZrO₂/C hybrid octahedrons. The excellent performance\nof Co/ZrO₂/C can be ascribed to the strong interface polarization\nand the suitable impedance matching, originating from the synergistic\neffect among the components.