Fabrication of bimetallic metal-organic frameworks derived Fe3O4/C decorated graphene composites as high-efficiency and broadband microwave absorbers

Abstract

Developing strong absorption and broadband microwave absorbers derived from metal-organic frameworks (MOFs) still remains a big challenge in the field of microwave absorption. Herein, iron zinc bimetallic metal-organic frameworks/reduced graphene oxide (FeZn-MOFs/RGO) precursors derived ferroferric oxide/carbon (Fe 3 O 4 /C) decorated graphene composites were fabricated via a solvothermal and carbonization two-step strategy. It was found that the morphology of carbon frameworks could be regulated from the traditional regular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe 3+ to Zn 2+ in the precursors. Moreover, results revealed that the molar ratios of Fe 3+ to Zn 2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe 3+ to Zn 2+ of 1:2 presented the optimal electromagnetic attenuation performance, i.e. the minimum reflection loss achieved −79.0 dB with a matching thickness of 2.76 mm and effective absorption bandwidth was as high as 5.8 GHz under a thin thickness of 1.8 mm and low filling ratio of 20.0 wt%. Additionally, the potential microwave dissipation mechanisms were illuminated. Therefore, our results would shed light on the development of high-efficiency and broadband microwave absorbing composites derived MOFs. • Fe 3 O 4 /C decorated graphene composites derived from bimetallic MOFs were prepared. • Morphology of carbon frameworks evolved from octahedron to pomegranate shape. • Microwave absorption was regulated by adjusting the molar ratios of Fe 3+ to Zn 2+ . • Strong absorption, broad bandwidth, thin thickness and low loading were achieved. • The potential microwave dissipation mechanism of attained composites was proposed.