An Ni-Co bimetallic MOF-derived hierarchical CNT/CoO/Ni2O3 composite for electromagnetic wave absorption

摘要

Rational modulation of electromagnetic parameters is necessary to master the electromagnetic wave absorption mechanism in order to optimize the material performance. To systematically explore the issue, in this work, we constructed the hierarchical CNT/CoO/Ni2O3 composite by the thermal decomposition of CNT/NiCo-MOF. Appropriately incorporating NiCo-MOF into the CNT matrix could significantly ameliorate the integrity of CNT-based conductive network structures, and the partial attributes of MOF could be preserved by heat treatment. Owing to the same electronic configuration (3d7), the Ni-3/Co2+ dual electric network is easy to form and has good synergistic action. The results showed that the CNT/CoO/Ni2O3 composite had a maximum absorption of - 49.6 dB at 9.47 GHz with a thickness of 2.5 mm. In addition, the absorption band with RL values less than - 10 dB could be manipulated between 10.16 and 14.03 GHz with a thickness of 2 mm. The remarkable improvement of microwave absorbing capability depended greatly on good cooperation between different metal ions, which contributed to the occurrence of multiple attenuations. The energy splitting and d-d electron transition of Ni-3 and Co2+ played a vital role in the optimization and advancement of electromagnetic performance, which offered new insights into the electromagnetic wave absorption mechanism. (C) 2021 Elsevier B.V. All rights reserved.