Synthesis of cobalt nanowires in aqueous solution under an external magnetic field.

Xiaoyu Li,Qin Long,Xuefei Lai,Lijuan Sun,Li Liao,Kenan Xie,Hu Wang

doi:10.3762/bjnano.7.91

Abstract

In contrast to the majority of related experiments, which are carried out in organic solvents at high temperatures and pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt nanowires are crystalline and mainly consist of cobalt as well as a small amount of platinum. Magnetic measurements showed that the resultant cobalt nanowires were ferromagnetic at room temperature. The saturation magnetization (Ms) and the coercivity (Hc) were 112.00 emu/g and 352.87 Oe, respectively.

Highlights

We have successfully prepared nickel and nickel/copper nanowires [14,15,16], and cobalt nanowires were synthesized using NaBH4 as initiator without surfactant in ethylene glycol solution with an external magnetic field under moderate conditions [12]
With polyvinylpyrrolidone (PVP) as surfactant, uniform linear cobalt nanowires with a mean diameter of about 100 nm were synthesized in aqueous solution under an external magnetic field at low temperature and atmosphere pressure for the first time
XRD patterns of the cobalt nanowires prepared with PVP and without PVP under an external magnetic field are shown in Figure 3a,b, respectively

Summary

Introduction

We have successfully prepared nickel and nickel/copper nanowires [14,15,16], and cobalt nanowires were synthesized using NaBH4 as initiator without surfactant in ethylene glycol solution with an external magnetic field under moderate conditions [12]. With polyvinylpyrrolidone (PVP) as surfactant, uniform linear cobalt nanowires with a mean diameter of about 100 nm were synthesized in aqueous solution under an external magnetic field at low temperature and atmosphere pressure for the first time.

Results

Conclusion