Tailored heterogeneous interface based on porous hollow In-Co-C nanorods to construct adjustable multi-band microwave absorber

Abstract

By rationally controlling the growth of zeolite-imidazolium salt skeleton (ZIF-67) nanoparticles on the hollow indium oxide (In2O3) and the subsequent pyrolysis process, In-Co-C hollow rod-like composites with multiple components were successfully prepared in this work. The synergistic impact of diverse components including In2O3, C, Co3InC0.75, and In not only optimizes impedance matching and improves conductive loss, but also creates significant interfacial polarization. Furthermore, the addition of Co source and pyrolysis temperature was found to have a significant affected on impedance matching and microwave absorption. The optimized In-Co-C sample displayed ultra-broad absorption bandwidth (EAB) of up to 7.12 GHz (10.88–18.0 GHz) at 2.26 mm thickness, which could cover the whole Ku band and part of X-band, outperforming the previously reported MOFs-derived composites. Furthermore, by adjusting the thickness to 2.91 mm and 4.01 mm, the EAB could cover the entire X band and most of the C band. The attenuation mechanisms were systematically investigated through the delta function method and ANSYS high-frequency structure simulator. These findings suggest that the MOFs-derived In-Co-C hollow nanorods could serve as high-performance microwave absorbers with ultra-broad absorption.