Herein, magnetic g-C₃N₄/g-carbon foams (CNFs) are fabricated via impregnating the as-prepared melamine–formaldehyde (MF) foams in iron acetylacetone (Fe(acac)₃) N,N-dimethylformamide (DMF) solutions with different concentrations followed by in situ pyrolysis. The corresponding electromagnetic wave (EMW) absorption behaviors are investigated. CNFs display solid 3D foam architectures with narrow and smooth skeletons, which consist of graphitic C₃N₄/carbon and CFe_15.1. The in situ as-synthesized α-Fe, Fe₃O₄, and Fe₃C particles are dispersed on the skeleton surface. With the increase of Fe elemental content, the EMW absorption performance of CNFs is enhanced. Among them, the minimum reflection loss value of CNF-3 is as low as −52.17 dB, with a matching thickness (t_m) of 4.25 mm and a broad effective absorbing bandwidth of 9.37 GHz. Besides, CNF-3 exhibits potential simultaneously effective absorption performance from the X-band to the Ku-band. This superior absorption behavior is attributed to Maxwell–Wagner–Sillars polarization, residual loss effect, enriched interface polarization effect, and macroporous structures. Further research studies demonstrate the potential application of CNF-3 as a reinforcing agent for PCL-based 3D printing EMW absorbers with improved mechanical properties. The corresponding EMW absorption matching frequency can be adjusted by the number of 3D printing layers.

中文翻译：

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具有优异电磁波吸收性能的超轻多孔磁性gC ₃ N ₄ / g-碳泡沫的合成及其作为3D打印EMW吸收剂的增强剂的应用

在这里，磁性gC ₃ N ₄ / g-碳泡沫（CNF）是通过将制备好的三聚氰胺-甲醛（MF）泡沫浸渍在乙酰丙酮铁（Fe（acac）₃）N，N-二甲基甲酰胺（DMF）溶液中制成的不同浓度后进行原位热解。研究了相应的电磁波（EMW）吸收行为。CNF显示具有狭窄且光滑骨架的固体3D泡沫结构，该结构由石墨C ₃ N ₄ /碳和CFe _15.1组成。在原位合成的的α-Fe，铁₃ Ò ₄和Fe ₃C颗粒分散在骨架表面上。随着Fe元素含量的增加，CNFs的EMW吸收性能增强。其中，CNF-3的最小反射损耗值低至-52.17 dB，且厚度匹配（t _m）为4.25毫米，有效吸收带宽为9.37 GHz。此外，CNF-3从X波段到Ku波段同时具有潜在的有效吸收性能。这种优异的吸收性能归因于麦克斯韦-瓦格纳-西勒斯极化，残余损耗效应，富集的界面极化效应和大孔结构。进一步的研究表明，CNF-3可以作为具有改善的机械性能的基于PCL的3D打印EMW吸收剂的增强剂。可以通过3D打印层的数量来调整相应的EMW吸收匹配频率。