Advanced Materials: TechConnect Briefs 2015Advanced Materials TechConnect Briefs 2015

Graphene Chapter 4

Synthesis, Characterization and magnetic properties of Graphene /Nickel nanocomposites: The role of reducing agent on nanoparticle size and morphology

M. Salimian, E. Titus, G. Goncalves, I. Bdkin, M. Ferro, J. Ventura, C.C. Dias
Nanoengineering Research Group (NRD), Portugal

pp. 172 - 175

Keywords: graphene, Nickel nanoparticles, composite

Graphene oxide (GO) synthesized by modified Hummers used as substrate for the controlled growth of nickel nanoparticles via hydrothermal treatment. Hydrazine hydrate were used as a complex agent for the effective control of the size, shape and distribution of nickel nanoparticles at GO surfaces, and at the same time it acts as a reducing agent for removing oxygen functional groups from GO surface. Four samples with different amount of Hydrazine hydrate (0.1, 0.5, 1 and 3 ml) were synthetized (Figure 2) and characterized by XRD, SEM and VSM. The results showed that GO was successfully reduced and functionalized with well dispersed nickel nanoparticles at its surface. More over the amount of hydrazine hydrate showed to play an important role in the size and morphology of the particles. It can be seen that the particles size vary from around 150 nm to 1μm and they have the morphology from fine spherical to spiky ones (fig 1). All the samples show the ferromagnetic behavior (fig2). The saturation magnetization of all samples are less than that comparing to the bulk nickel likely due to the surface oxidation, however sample (a) shows the maximum magnetic saturation of 23 emu g-1. The maximum coercivities (Hs) and remanence (Mr) are 183 Oe and 3.5 emu g-1 respectively which belongs to sample (b) arising from the fact that the magnetic properties are shape anisotropy and dipolar interactions dependence.