Effect of Current Density on Electrochemical Shape Control of Pt Nanoparticles

• Shape-controlled Pt nanoparticles were prepared by a galvanostatic technique.
• Pt ions were produced by oxidative dissolution of the Pt anode.
• The shapes of Pt nanoparticles could be controlled by the current densities.
• The reduction rate of Pt ions and dissolution rate of the Pt anode were key factors.

Shape-controlled Pt nanoparticles were electrochemically prepared on a graphite plate by galvanostatic electrolysis using an electrolytic cell containing a graphite plate cathode and a Pt sheet anode. The galvanostatic electrolysis was performed in a 0.5 M HNO3 solution at 50 °C, and cubic nanoparticles were obtained by appropriately controlling cathodic and anodic current densities only. An extremely small amount of Pt ions produced by oxidative dissolution of the Pt anode diffused to the graphite cathode through the electrolyte solution and were reduced to form Pt nanoparticles having a cubic structure. Balancing the reduction rate of Pt ions at the graphite cathode and the dissolution rate of the Pt anode significantly influenced the shape of deposited Pt nanoparticles.