Surface Electrochemistry of Pt–Ni Thin-Film Formations
Alasdair Fairhurst, Benjamin J. Ransom, Dominik Haering, Chaewon Lim, Ethan J. Schoettler, Vojislav R. Stamenković
Abstract
Identifying materials that are both active and durable remains at the frontier of research in electrocatalysis. Platinum alloys offer favorable kinetic properties for the oxygen reduction reaction and are heavily utilized in the deployment of polymer electrolyte membrane fuel cells. Nevertheless, the balance between the activity and durability of Pt alloys is an ongoing debate in the field. In this work, a thin-film approach is applied to explore the surface electrochemistry of finely tuned Pt–Ni near-surface formations. The extended thin-film surfaces were obtained by physical vapor deposition in a high-vacuum environment, and surface properties were controlled and tuned for geometric surface area, composition, and morphology. Thermal annealing followed by acid leaching was used to examine the impact on both activity and durability. Specific focus was placed on Pt-skin formation to explore its protective properties against dissolution while enhancing activity for the ORR.