Surfactant-assisted solvothermal synthesis of pure nickel submicron spheres with microwave-absorbing properties.

Heng Guo,Jin Yang,Jian Yang,Xiaobin Niu,Bingxue Pu,Yajun Zhou,Boateng Bismark,Handong Li,Haiyuan Chen

doi:10.1186/s11671-016-1562-y

Abstract

Pure metallic nickel submicron spheres (Ni-SSs), flower-like nickel nanoflakes, and hollow micrometer-sized nickel spheres/tubes were controllably synthesized by a facile and efficient one-step solvothermal method with no reducing agent. The characteristics of these nickel nanostructures include morphology, structure, and purification. Possible synthesis mechanisms were discussed in detail. The resultant Ni-SSs had a wide diameter distribution of 200~800 nm through the aggregation of small nickel nanocrystals. The ferromagnetic behaviors of Ni-SSs investigated at room temperature showed high coercivity values. Furthermore, the microwave absorption properties of magnetic Ni-SSs were studied in the frequency range of 0.5–18.0 GHz. The minimum reflection loss reached −17.9 dB at 17.8 GHz with a thin absorption thickness of 1.2 mm, suggesting that the submicron spherical structures could exhibit excellent microwave absorption properties. More importantly, this one-pot synthesize route provides a universal and convenient way for preparation of larger scale pure Ni-SSs, showing excellent microwave absorption properties.

Highlights

With the rapid development of nanoscience and nanotechnology, magnetic nanostructured materials have attracted significant interest because of their interesting optical, electrical, and catalytic properties, as well as response and manipulability under magnetic fields [1,2,3]
The attenuated permeability and weak magnetocrystalline anisotropy may limit its applications at higher frequencies due to the dimension decrease and the repression of skin effect [21]. This phenomenon obviously shows that the physical and chemical performances of Ni nanomaterials strongly depend on the makeup, structure, size, nanoscale morphology, and polydispersity [22, 23] which are the key factors for its further application including the electromagnetic wave absorption characteristic and intensity
Close observation showed that these 3D flower-like hollow structures were made of dozens of crispate nanoflakes, which was similar to the Ni-600 flowers

Summary

Introduction

With the rapid development of nanoscience and nanotechnology, magnetic nanostructured materials have attracted significant interest because of their interesting optical, electrical, and catalytic properties, as well as response and manipulability under magnetic fields [1,2,3]. As an important class of ferromagnetic transition metal, Ni nanoparticles are emerging and displaying many characteristics such as high magnetism, high surface area, large surface energy, excellent chemical stability, low melting point, resource-rich, and low cost [10,11,12] They are widely used in several important technological fields such as magnetic materials catalysts, magnetic fluids, microwave devices, and high-sensitive gas sensors [13,14,15]. The attenuated permeability and weak magnetocrystalline anisotropy may limit its applications at higher frequencies due to the dimension decrease and the repression of skin effect [21] This phenomenon obviously shows that the physical and chemical performances of Ni nanomaterials strongly depend on the makeup, structure, size, nanoscale morphology, and polydispersity [22, 23] which are the key factors for its further application including the electromagnetic wave absorption characteristic and intensity. The control of the Ni/Ni-based nanomaterials fabrication is sensitive to the preparation methods

Methods

Results

Conclusion