Effect of PVP on the Morphology and Growth of Cu Hierarchical Nanostructures Prepared by Electroless Deposition

Octahedral Cu hierarchical nanostructures were prepared by electroless deposition in aqueous solution at 80 °C. Polyvinyl pyrrolidone (PVP) was employed as the protective and structure directing agent to prevent oxidation and agglomeration of the Cu products. Addition of higher amounts of PVP (about 1.275 g) resulted in smaller but irregularly-shaped Cu nanoparticles. The Cu nanoparticles have a mean particle diameter of about 200 nm with excellent size distribution. On the other hand, Cu octahedrals were produced when 0.425 to 0.850 g PVP was used. In situ mixed potential monitoring of the solution during electroless deposition revealed that the mixed potential was more positive at larger amounts of PVP. This can be attributed to slower reduction rate due to the decrease in the activity of Cu(II) ions. Consequently, smaller Cu nanoparticles were produced.