Controllable synthesis, formation mechanism, and enhanced microwave absorption of dendritic AgFe alloy/Fe3O4 nanocomposites†,CrystEngComm

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Controllable synthesis, formation mechanism, and enhanced microwave absorption of dendritic AgFe alloy/Fe3O4 nanocomposites†
CrystEngComm ( IF 2.6 ) Pub Date : 2018-02-19 00:00:00 , DOI: 10.1039/c7ce02223a
Chen Jin _{1,

2,

3,

4} , Zidong He _{1,

2,

3,

4} , Yanting Zhao _{1,

2,

3,

4} , Yefei Pan _{1,

2,

3,

4} , Wenhua Wu _{1,

2,

3,

4} , Xiaojuan Wang _{1,

2,

3,

4} , Guoxiu Tong _{1,

2,

3,

4}

Affiliation

Single-crystalline dendritic AgFe alloy/Fe₃O₄ nanocomposites were successfully synthesized through galvanic replacement using Fe nanofibers as reducers and templates. The molar ratio of Ag⁺/Fe²⁺ (δ) and the aspect ratio of Fe nanofibers influence the compositions and sizes of the nanocomposites, respectively. The selective attachment at the {220} planes and anisotropic growth along the (111) plane affect the growth of dendritic nanocomposites. The composition-dependent static magnetic and microwave electromagnetic characteristics were studied systematically. Dendritic nanocomposites are typically ferromagnetic. The M_s decreases and H_c increases with increasing δ because of the increased content of antiferromagnetic Ag. Nanocomposites with δ = 1 : 1 and 2 : 1 exhibit significantly stronger absorption, thinner sample thickness, and lower bandwidth than pure Ag nanoparticles because of enhanced dielectric loss, magnetic loss, resonance absorption, and impedance matching. The bandwidth (R_L ≤ −10 dB) is 4.85 GHz, which corresponds to the minimum R_L value of −43.5 dB, and the absorption frequency range (R_L ≤ −20 dB) is 7.68 GHz. This work provides a general strategy for preparing dendritic Ag-based nanocomposites and a basis for further studies on using hierarchical heterostructures as microwave-absorbing materials.

中文翻译：

树枝状AgFe合金/ Fe ₃ O ₄纳米复合材料的可控合成，形成机理和增强的微波吸收†

以Fe纳米纤维为还原剂和模板，通过电流置换成功地合成了单晶树枝状AgFe合金/ Fe ₃ O ₄纳米复合材料。Ag ⁺ / Fe ²⁺（δ）的摩尔比和Fe纳米纤维的长径比分别影响纳米复合材料的组成和尺寸。{220}平面的选择性附着和沿（111）平面的各向异性生长影响树枝状纳米复合材料的生长。系统研究了与成分有关的静磁和微波电磁特性。树状纳米复合材料通常是铁磁性的。的中号_小号降低，ħ _Ç由于反铁磁Ag含量的增加，δ随δ的增加而增加。δ = 1：1和2：1的纳米复合材料由于介电损耗，磁损耗，共振吸收和阻抗匹配的增强，与纯银纳米颗粒相比，具有明显更强的吸收性，更薄的样品厚度和更低的带宽。带宽（ř_大号≤-10分贝）为4.85千兆赫，它对应于最小ř_大号的-43.5 dB值，和吸收的频率范围（[R_大号≤−20 dB）是7.68 GHz。这项工作为制备树枝状Ag基纳米复合材料提供了一般策略，并为进一步研究使用分层异质结构作为微波吸收材料奠定了基础。

更新日期：2018-02-19

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