Earthworm-like (Co/CoO)@C composite derived from MOF for solving the problem of low-frequency microwave radiation

For the rapid progress of microwave communication, electromagnetic technique and various electronic instruments, the low-frequency microwave radiation has become a serious problem in many situations. Herein, a novel Co-MOF derived (Co/CoO)@C composite with earthworm-like was prepared via facile hydrothermal and annealing route. The relevant microstructures and electromagnetic wave absorbing properties could be regulated by the annealing temperature, the optimal performance of as-prepared composite can be obtained under the annealing temperature of 600 °C i.e. the maximal RL is − 40.98 dB at 0.89 GHz with relevant efficient absorbing bandwidth of 0.43–1.88 GHz for the thickness of 3.5 mm. Moreover, a widest low-frequency efficient absorbing bandwidth of 0.68–3 GHz can be also achieved for only 2.36 mm thickness. The enhanced interfacial polarization loss, strong conduction loss along earthworm-like carbon pathways, appropriate hysteresis loss, excellent eddy-current and natural resonance loss stimulated in magnetic nanoparticles are main reasons for its remarkable low-frequency absorption, suggesting the as-prepared composite is a selectable candidate to solve the problem of low-frequency microwave radiation.