Hierarchically Porous Carbon/α‐Fe@Fe3C Absorbers Derived from Luffa Sponge with Efficient Microwave Absorption

• Published in: ChemistrySelect (Weinheim) Vol. 5; no. 47; pp. 15075 - 15083
• Main Authors: Zheng, Qi, Yu, Meijie, Wang, Wen, Liu, Siyu, Liang, Xuechen, Wang, Chengguo, Dai, YouYong, Gao, Xueping
• Format: Journal Article
• Language: English
• Published: 18.12.2020
• Subjects: Attenuation constant; Biomass; Dielectric loss; Microwave absorption; Nanoparticles
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202004281

Biomass‐based carbon materials have attracted much attention in the field of microwave absorption because of their light weight, environmental friendliness, low cost and high efficiency. In this work, carbon matrix of porous microtubule structure with different magnetic particles was synthesized from natural luffa sponge by a simple calcination process. The carbon matrix possesses hierarchical porous structures including micrometer‐scale tubular channels, nanometer‐scale macrospores, mesopores and micropores, of which microspores are the most. The Fe3O4, FeO/α‐Fe, α‐Fe/γ‐Fe and α‐Fe/Fe3C particles were formed in the temperature range of 700–1000 °C. The porous carbon/α‐Fe@Fe3C composites obtained at 1000 °C exhibit excellent microwave absorption (MA) performance, its minimum reflection loss can reach −48.9 dB with only a thickness of 1.5 mm, and the effective absorption bandwidth (RL≤−10 dB) is 3.86 GHz. The porous structure, synergies between dielectric loss and magnetic loss, high attenuation constant are the key factors for good MA performance. Biomass‐based carbon materials are cheap, widespread, lightweight and environmentally friendly, thus microwave‐absorbing materials stemming from biomass have gained increasing attention. In this paper, we used natural luffa sponge fibers to synthesized porous carbon matrix with magnetic particles through a simple soaking and calcination method. These composites have excellent microwave absorption properties because of their special hierarchically porous structures. The minimum reflection loss can reach −48.9 dB with only a thickness of 1.5 mm.