Cobalt(III) ammine complexes as precursors in the synthesis of cobalt nanoparticles

Abstract

Cobalt nanoparticles have been prepared by the chemical reduction of [Co(NH₃)₆]Cl₃, [Co(NH₃)₅Cl]Cl₂, and [Co(NH₃)₅ONO]Cl₂ in alcoholic solution. The reaction of these complexes with hydrazine as a reducing agent were carried out at 70 °C and pH = 10–12. The metallic nanoparticles were characterized by using X-ray powder diffraction, IR spectroscopy, scanning electron microscopy, and vibrating sample magnetometer. The synthesized cobalt nanoparticles have different morphologies and nanosheet distributions. The Co1 has a sheet thickness ranging from 15 to 40 nm and shows an aggregated dendrite structure. On the other hand, Co2 has a cactus like morphology with a nanosheet thickness ranging from 15 to 35 nm. The Co3 nanoparticles were pompon-like microspheres in shape and aggregated powders with a nanosheet thickness ranging from 10 to 45 nm. This work presents a novel approach for the preparation of metallic nanoparticles via metal complexes.

Keywords:

• Cobalt(III) complex
• Chemical reduction
• Cobalt nanoparticles
• Magnetic materials.

Acknowledgement

The authors are grateful to the University of Kashan for supporting this work by Grant No. 256736/2.