MOF-derived core-shell structured Cu₉S₅/NC@Co₃S₄/NC composite as a high-efficiency electromagnetic wave absorber

Constructing specific microstructures and designing multicomponent composites are regarded as effective approaches to obtaining high-efficiency electromagnetic (EM) wave absorbing materials. Herein, core-shell structured Cu₉S₅/N-doped carbon@Co₃S₄/N-doped carbon (Cu₉S₅/NC@Co₃S₄/NC) composites derived from Cu₃(BTC)₂@ZIF-67 were synthesized by facile carbonization and sulfidation processes. The Cu₉S₅ particles are embedded in the interior and surface of the carbon skeleton, and the Co₃S₄/NC particles are uniformly distributed on the surface of the carbon skeleton. Compared with Cu₉S₅/NC and Co₃S₄/NC, the Cu₉S₅/NC@Co₃S₄/NC composite displays improved impedance matching properties and much better EM wave absorbing properties. The minimum reflection loss (RL_min) reaches −41.6 dB at 10.52 GHz with a thickness of 2 mm. In addition, the effective absorption bandwidth (EAB, RL < −10 dB) is 4.08 GHz (12.73–16.81 GHz) with un ultrathin thickness of 1.5 mm. This work offers a facile strategy for synthesizing MOF-derived metal sulfides/carbon composites as EM wave absorption materials with strong absorption properties, a wide absorption bandwidth and ultrathin thickness.