High-aspect-ratio iron nanowires: magnetic field-assisted in situ reduction synthesis and extensive parametric study

Abstract

High-performance iron nanowires have attracted wide attention from researchers due to their 'controllable' arrangement distribution by magnetic fields. In this paper, a simple magnetic field assisted in situ reduction method was proposed to synthesize Fe NWs with high aspect ratio, smalldiameter, and good dispersion. A detailed parametric study determining the relationship among the final morphologies of the products and magnetic field, injection sequence of sodium borohydride that was injected into ferrous sulfate heptahydrate, reactant concentration, and injection rate is presented. The as-synthesized Fe NWs were analyzed by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and vibrating sample magnetometry. A plausible mechanism for the formation of high-aspect-ratio Fe NWs is proposed. The SEM images showed the dependence of the NWs morphology and aspect ratio on synthesis parameters. Magnetic field and injection sequence showed considerable influences on the synthesis of high-aspect-ratio Fe NWs. In the absence of magnetic field or with the changes in injection sequence, only the Fe flakes were obtained. The NWs diameter decreased, and the aspect ratio increased with the increase in injection rate. The FeSO 4 •7H 2 O and NaBH 4 concentration considerably influenced the aspect ratio of the product, which increased first, decreased, and then increased again with the increase in FeSO 4 •7H 2 O concentration. Meanwhile, the product aspect ratio increased and then became saturated with the increase in NaBH 4 concentration Thus, an optimum synthesis process was obtained, with the average aspect ratio of 350, and the average diameter of 60 nm. The results reported in this paper provide a basis for optimizing the growth of Fe NWs by magnetic field-assisted method.

Improved Stretchable and Sensitive Fe Nanowire-Based Strain Sensor by Optimizing Areal Density of Nanowire Network

“…High-aspect-ratio Fe NWs were synthesized according to our previously reported method [ 19 ]. First, 2.78 g of FeSO 4 ·7H 2 O and 5.30 g of NaBH 4 were separately dissolved in 100 mL of pure water to prepare solutions.…”

“…Further, in addition to the characteristics of metal nanowires themselves, the filling ratio of metal nanowires also has a great impact on the sensing performance, but little attention has been paid to it [ 13 , 14 ]. Studies have explored the mechanism of the synthesis of Fe NWs by the magnetic field-assisted in situ reduction method [ 19 ], mastered the method of controlling the aspect ratio of Fe NWs, and studied their potential application in electromagnetic absorption [ 20 ]. It was found that the high aspect ratio of Fe NWs is beneficial for obtaining a good conductive network with a low filling mass fraction.…”

Recent Progress in Iron-Based Microwave Absorbing Composites: A Review and Prospective

“…One-dimensional wire-like Fe has the advantages of a small size and the large specific area, which can improve the anisotropy and resonance frequency of magnetic materials [51]. For example, Fe nanofibers, Fe nanowires, Fe nanochains, etc., all have good microwave absorption performance and are the focus of current research.…”

Nanostructured Films of Ordered Fe Nanowires for High-Performance Transparent Electromagnetic Interference Shielding

“…To achieve the objectives outlined above, we synthesized monodisperse Fe NWs with a high aspect ratio using the procedure described in our previous report. 26 We deposited a series of anhydrous ethanol dispersions with different contents of Fe NWs on polyethylene terephthalate (PET) substrates using the drop-coating method. With the help of a Halbach array of magnets, we formed an ordered structure of Fe NWs.…”