Enhanced rate electrodeposition of Pt–Ni thin films via acetate complexation

Platinum-nickel alloys are important materials for electronics and electrocatalysis applications. While current synthesis methods typically use physical or chemical vapor deposition, electrodeposition offers a low cost and effective alternative. The co-electrodeposition of platinum and nickel presents major challenges, including widely differing deposition potentials, with hydrogen gas evolution at the Ni ion reduction potential. Past investigations used millimolar Pt solution concentrations in order to overcome these challenges. However, these impose ion transport limitations necessitating very low deposition rates. Here, we demonstrate the use of complexation agents and hydrogen evolution suppressants at appropriate pH to demonstrate platinum and nickel co-deposition at >25% atomic nickel and rates substantially higher than previous investigations. A nearly one-to-one platinum to nickel thin film was achieved by electrodepositing in a 0.025M · H2PtCl6, 0.2M · NiSO4, and 1M acetate bath at pH 6.8, and a one-to-three platinum to nickel concentration. Acetate adsorption and complexation with platinum and nickel ions significantly alter hydrogen generation at the deposition surface as well as the metal ion solution transport properties.