Behavior of precipitation and morphological, structural properties during the synthesis of spherical Ni and Ni0.95M0.05(M=Cu, Cr, Co, Fe) nano-particles

Abstract

Spherical Ni and Ni0.95M0.05(M=Cu, Cr, Co, Fe) nano-particles were synthesized using hydrazine reduction method. The objective of this study is to investigate how the different metallic species affect the reduction rate when nano-sized metallic particles are synthesized by the precipitation method. It was found that the pH and reaction temperature had significant influence over the size and morphology of the synthesized metallic nano-particles. Ni0.95Cu0.05 solution showed highest reduction precipitation rate, while Ni0.95Cr0.05 showed slowest rate among the metallic species investigated in this study. At higher reaction temperature, the precipitated metallic particles showed higher degree of crystallinity. The particles synthesized at higher the pH had smaller surface area because the surface of the particles became smoother. It was found that the crystallographic lattice either contract or expand depending on the substituting metallic species. It is concluded from this study that the morphology and size of the spherical Ni and Ni0.95M0.05 nano-particles can be controlled by solution temperature and pH as well as metallic species added. This is due to different reaction rate resulted from difference in reduction potential and activation energy at different temperature and pH.