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

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 (Fe3O4/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 reg-ular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe3+ to Zn2+ in the precursors. Moreover, results revealed that the molar ratios of Fe3+ to Zn2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe3+ to Zn2+ 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%. Addi-tionally, 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.

Automated summary

This study successfully fabricated iron-zinc bimetallic metal-organic frameworks/reduced graphene oxide composites with excellent microwave absorption performance by controlling the molar ratios of Fe3+ to Zn2+. The results also revealed the significant effects of molar ratios on the properties of the composites.