Construction of cobalt zinc metal-organic frameworks derived Co/CoO/C composites toward broadband and high-efficiency electromagnetic wave absorption

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2024-11, Vol.703, p.135389, Article 135389
• Main Authors: Shu, Ruiwen, Zhang, Jinling, Liu, Baohua
• Format: Article
• Language: English
• Subjects: Electromagnetic wave absorption; Magnetic composites; Metal-organic frameworks; Morphology regulation; Pyrolysis
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2024.135389

The fabrication of novel carbon-based electromagnetic wave (EMW) absorbers with broad absorption bandwidth, strong absorption strength, low filler loading ratio and thin matching thickness remains a challenging task. Metal-organic frameworks (MOFs) are widely recognized as ideal self-sacrificial templates for the construction of carbon-based EMW absorbers. In this work, bimetallic CoZn-MOFs derived Co/CoO/C composites were prepared by combining magnetic stirring with subsequent pyrolysis treatment. The results showed that the morphology of carbon skeletons evolved from an irregular agglomerate to a uniform hexagonal star shape and then to an agglomerate again by reducing the molar ratio of Co2+ to Zn2+. Remarkably, excellent EMW absorption capacity in the Ku-band was achieved through carefully regulating the molar ratio of Co2+ to Zn2+. When the filling ratio was 20 wt%, the prepared Co/CoO/C composite exhibited the best EMW absorption performance with the minimum reflection loss of −64 dB at a thickness of 1.79 mm and the maximum effective absorption bandwidth of 6 GHz at a thickness of 2.14 mm. Furthermore, the radar cross section in the far-field was simulated by computer simulation technique. In addition, the possible EMW attenuation mechanism was proposed. Therefore, the results of this paper could be helpful for developing carbon-based magnetic composites derived from MOFs as broadband and high-efficiency EMW absorbers. [Display omitted] •CoZn-ZIFs derived Co/CoO/C composites were prepared by a facile two-step method.•The prepared Co/CoO/C composite showed a unique hexagonal star morphology.•Electromagnetic absorption was regulated by changing molar ratios of Co2+ to Zn2+.•Strong absorption and wide bandwidth were achieved at a low filler loading ratio.•Minimum radar cross section value was −60.6 dB m2 under the far-field condition.