蛋黄-蛋壳结构 Fe_(3)O_(4)@NC纳米立方体的制备及其吸波性能

Preparation of yolk-shell structured Fe_(3)O_(4)@NC nanocubes for high-performance microwave absorption

以Fe_(2)O_(3)纳米立方体为模板剂,通过盐酸多巴胺原位聚合及煅烧处理制备了氮掺杂碳包裹Fe_(3)O_(4)(Fe_(3)O_(4)@NC)核壳结构立方体,进一步通过控制盐酸蚀刻Fe_(3)O_(4)的时间,得到新颖的蛋黄-蛋壳结构Fe_(3)O_(4)@NC纳米吸波材料.通过对其形貌、组成、磁性能及电磁特性的表征,讨论了结构对产物吸波性能的影响及该复合体系的吸波机理.结果表明:由于强的自然共振、交换共振、涡流损耗、多重介电弛豫和优异的匹配特性,蛋黄-蛋壳结构Fe_(3)O_(4)@NC在2~18 GHz频段展示了优异的低频、高频、宽带、高吸收特性;当匹配厚度为2 mm时,对应有效吸收带宽为4.24 GHz;其最大反射损耗为-22.0 dB(14.38 GHz).此类蛋黄-蛋壳结构Fe_(3)O_(4)@NC复合材料在电磁波吸收领域具有广泛的应用研究前景.

N-doped carbon-coated Fe_(3)O_(4)(Fe_(3)O_(4)@NC)core/shell cubic microwave absorbing agent was prepared by in-situ polymerization of dopamine hydrochloride and subsequent calcination treatment by using Fe_(2)O_(3) nanocube as template.The annealed product was dispersed in 4 mol/L HCl solution and etched for 45 min to partially remove the Fe_(3)O_(4)core,which led to the formation of yolk-shell structured Fe_(3)O_(4)@NC nanocubes.Due to the strong natural resonance,exchange resonance,eddy current loss,multiple dielectric relaxation,and good impedance matching,the yolk-shell structured Fe_(3)O_(4)@NC exhibited superior performance with low frequency,high frequency,wide bandwidth,and high absorption at the frequency range 2~18 GHz.The maximal reflection loss(R L)was-22.0 dB at 14.38 GHz,and the corresponding broad effective bandwidth(R L≤-10 dB)was 4.24 GHz with a 2 mm matching thickness.The yolk-shell structured Fe_(3)O_(4)@NC nanocubes would have a wide application prospect in the field of microwave absorption.