Morphology control in synthesis of nickel nanoparticles in the presence of polyvinylpyrrolidone (PVPK30)

Nickel nanoparticles with different morphologies have been synthesized with polyvinylpyrrolidone (PVPK30) as structure-directing agent through a chemical reduction process. SEM, TEM and selected-area electron diffraction (SAED) were employed in the analysis of morphological characteristics of nickel nanoparticles. It was found that nickel nanoparticles are formed by the aggregation of nanoscale nickel crystallites, and particle morphology was strongly dependent on the PVPK30 concentration. In addition, crystallite size and formation time of nickel nanoparticles increased with the increasing PVPK30 concentration. PVPK30 additive seems to influence the three steps of nickel particle precipitation: nucleation, crystal growth and aggregation. The resultant spherical nickel nanoparticles showed high coercivity.