Study on the preparation of NiCo-ZnO@NPC composites and their microwave absorbing properties

Abstract

Metal-organic frameworks (MOFs) have garnered significant attention as promising microwave absorption materials. However, the nitrogen-doped porous carbon (NPC) generated by high-temperature carbonization treatment still has problems such as impedance mismatch and poor dielectric properties, which hinder their practical application. This work presents the synthesis of a trimetallic ZnNiCo-MOF-74 composite using the solvothermal method, and the subsequent preparation of NiCo-ZnO@NPC composites via a straightforward carbonization process, demonstrating that both exceptional dielectric and magnetic losses can be obtained in one one-step process. The results reveal that the microwave absorption performance of the composites can be effectively tuned by varying the Zn²⁺ content, and at a 5 % Zn content, the composites exhibited a minimum reflection loss (RL_min) of −60.4 dB at 9.44 GHz with an effective absorption bandwidth of 4.1 GHz. This demonstrates the composites have potential as lightweight and high-performance microwave absorbers.