Room-Temperature Synthesis of Cobalt Nanoparticles in Aqueous Solution

Abstract

A fast low-cost approach to the fabrication of metallic cobalt (Co) nanoparticles is proposed. Metallic Co nanoparticles with mean diameters of 24−112 nm are synthesized by electroless deposition (chemical reduction) in an aqueous solution at room temperature. H 2 PtCl 6 and N 2 H 4 are used as a nucleating agent and a reductant, respectively. The Co(II) reduction rate and the mean particles size are strongly influenced by the concentration of the nucleating agent, which are observed by in situ mixed potential measurement and electron microscopy. The mixed potential shifts negatively with increasing H 2 PtCl 6 , which results to fast reduction of Co(II) ions. Small Co nanoparticles are thus formed.

Investigation of Platinum-Catalyzed Formation of Cobalt Nanoparticles by Mixed Potential

“…Adding more H 2 PtCl 6 results in an instantaneous drop of the mixed potential below E Co(II)/Co , and a spontaneous change in the color of the solution. Because of the acceleration of the reaction rates with higher amounts of H 2 PtCl 6 , it is plausible that the Pt nanoparticles formed from H 2 PtCl 6 act as catalysts for Co deposition, as well as nucleation sites for Co nanoparticles [7][8][9][10][11]. To elucidate the influence of H 2 PtCl 6 on the reaction rate, the change in mixed potential during Pt deposition is observed.…”

The Influence of Bath Concentration on Particle Size of Cobalt Nanoparticles

“…Nanoparticles materials refer to those materials (crystallites, clusters, or molecules) have sizes less than 100 nm [1]. The properties of nanoparticle materials are superior to those of conventional polycrystalline grain counterpart.…”