Electrolytic approach towards the controllable synthesis of symmetric, hierarchical, and highly ordered nickel dendritic crystals

Abstract

Symmetric Ni dendritic crystals, which consist of a long main trunk and highly ordered secondary and tertiary branches, have been successfully synthesized via a simple and inexpensive electrolytic process in ethylene glycol solution. The length of the main trunk is about 10 μm, and that of each branch is about 0.5–1.5 μm with a width of 210 nm. Microstructure characterization indicates that all the secondary and tertiary branches in the dendritic structures are almost parallel to each other, and these branches consist of spherical particles with sizes ranging from 40 to 120 nm. A possible growth mechanism of magnetic pure metal dendritic crystals was proposed after investigating four different stages during the electrolytic process. Meanwhile, we found that the morphology of Ni dendritic structures could be controlled by simply adjusting the experiment parameters such as concentration of NiCl2, voltage and temperature in the electrolytic reaction. Additionally, measurements of magnetic properties at 300 K indicates that the as-prepared Ni dendritic crystals possess lower saturation magnetism (Ms, 48.47 emu g−1) and higher coercivity (Hc, 189.3 Oe) than that of corresponding bulk nickel, which could be attributed to their special dendritic structure.