Construction of ZIF-67 derived multi-interfacial composites embedded in carbonized pomelo peel for enhanced microwave absorption with 8 wt% filler loading

The development of lightweight, environmentally friendly, and cost-effective microwave absorbers with robust absorption capabilities represents a challenging yet imperative undertaking. Herein, we present a methodology wherein derived ZIF-67 (abbreviated as Co/C) embedded in carbonized pomelo peel (CPP) through a combination of pyrolysis and in-situ growth methods, demonstrates effectiveness in microwave absorption. The Density Functional Theory (DFT) provides a comprehensive analysis of the preparation and operating principles underlying the CPP@Co/C absorber. The modification of CPP with Co/C not only facilitates the creation of numerous multiple interfaces but also mitigates impedance mismatching phenomena associated with CPP. It indicates that CPP@Co/C-150 achieves a remarkable 90% wave radiation within the frequency range of 3.52–18 GHz at a mere 8 wt% loading, covering the entire C, X, and Ku bands. Furthermore, CPP@Co/C-100 exhibits a minimum reflection loss (RLmin) value of −42.5 dB at a thickness of 1.82 mm, with an effective absorption bandwidth (EAB) extending to 5.2 GHz at 2.00 mm. This represents a substantial increase of 340% and 209% compared to CPP absorbers, respectively. The exceptional absorption performance is attributed to favorable impedance matching, conductivity loss, polarization loss, and magnetic loss mechanisms. This study introduces novel strategies and benchmarks for the production of low-cost and environmental-friendly microwave absorbers with a straightforward preparation process.