Effect of pH on Formation of Nickel Nanostructures through Chemical Reduction Method

The synthesis of nickel (Ni) nanostructures through chemical reduction method using hydrazine (N2H4.6H2O) as the reducing agent and ethylene glycol (EG) as the surfactant is reported. The synthesis was conducted in 1 hour of heating at temperature of 60 °C. Sodium hydroxide (NaOH) was used to control the pH of solutions. Scanning Electron Microscopy (SEM) and Tranmission Electron Microscopy (TEM) revealed that by varying [OH−]/[Ni2+] molar ratio, various formation of Ni nanostructures with size between 20 to 800 nm were obtained. Changing the pH from 6 to 12 resulted in formation of Ni wool-like nanostructure composed from chain-like nanostructure particles. Presence of crystallized particles in FCC phase was confirmed with phase analysis using X-ray diffraction (XRD). It showed formation of pure Ni metal nanoparticles without any impurity only occur when [OH−]/[Ni2+] molar ratio was tailored to higher than four (4). Magnetization value of Ni wool-like nanostructures measured by vibrating sample magnetometer (VSM) was 36.1 emu/g, relatively higher compared to bulk and spherical Ni nanoparticles.