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 (RLmin) 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.