Tunable Dielectric Performance Derived from the Metal-Organic Framework/Reduced Graphene Oxide Hybrid with Broadband Absorption

In terms of microwave absorption, dielectric performance acts vital but has negative characteristics in attenuation and impedance matching. In this study, ZnO/nanoporous carbon (NPC)/reduced graphene oxide (RGO) materials have been fabricated through a simple and valid hydrothermal method derived from Zn metal-organic frameworks (MOFs). By changing the molar ratio of the precursors, the permittivity of the ZnO/NPC/RGO can be calculated, and the greatest balance between energy conservation and impedance matching eventually emerged with the addition of 4 mL of GO. It could be found that, at 14 GHz, a thin sample consisting of 40 wt % ZnO/NPC/RGO in the wax matrix exhibited minimum reflection loss of -50.5 dB with a thickness of 2.4 mm, and with a thickness of 2.6 mm, the effective microwave absorption bandwidth coverage is from 9.6 to 17 GHz. It is worth mentioning that we have also interpreted the relationships between the highest reflection loss values and matching thicknesses. This work not only proposes that ZnO/NPC/RGO samples are able to function as a perfect absorbent with broad frequency bandwidth and strong absorption but also provides better candidates in designing other lightweight microwave absorbents.