Journal
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Volume 633, Issue -, Pages 43-52Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.jcis.2022.11.078
Keywords
Metal -organic framework; Pyrolysis; Porous carbon; Magnetic composite; Electromagnetic absorption
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In this study, porous carbon-based magnetic composites derived from iron zinc bimetallic MOF were prepared and their electromagnetic parameters and absorbing properties were regulated by changing the pyrolysis temperature. The composite pyrolyzed at 700 degrees C showed the best EM absorption performance, with a minimum reflection loss of about 60 dB and a broad absorption bandwidth of 4 GHz (8-12 GHz, covering the whole X band) at a matching thickness of 2.5 mm and a filler loading ratio of 40 wt%.
The fabrication of broadband and high-efficiency electromagnetic (EM) wave absorbers remains a huge challenge. Metal-organic framework (MOF) with large porosity and high specific surface area has been considered as a promising precursor for the preparation of novel EM wave absorbers. In this work, porous carbon-based magnetic composites derived from iron zinc bimetallic MOF were prepared by the two-step method of solvothermal reaction and high-temperature pyrolysis. Results of micromorphology analysis demonstrated that the morphology of carbon frameworks evolved from octahedron, polyhedron, sphere to porous sphere-like shape with the increase of pyrolysis temperature. Furthermore, the EM parameters and absorbing properties of obtained composites were regulated through simply changing the pyrolysis temperature. It was noteworthy that the as-prepared Fe3O4/C composite pyrolyzed at 700 degrees C exhibited the best EM absorption performance. The minimum reflection loss was as large as similar to 60 dB and broad absorption bandwidth reached up to 4 GHz (8-12 GHz, covering the whole X band) at a matching thickness of 2.5 mm and a filler loading ratio of 40 wt%. Furthermore, the maximum absorption bandwidth could be enlarged to 5.4 GHz via reducing the matching thickness to 1.85 mm. Additionally, the probable EM attenuation mechanisms of attained composites were proposed. The results of this study would provide a reference for the preparation of porous carbon-based composites as broadband and highefficiency EM wave absorbers.
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