NOVELTY - The process comprises: providing a metal layer having a surface energy of greater than 2.5 J/m2; depositing a continuous, conformal layer of platinum or platinum alloy on the metal layer by hydrogen plasma assisted atomic layer deposition, where the layer of the platinum or platinum alloy has a thickness of less than 4 nm; and removing metal oxides from the metal layer. The step of providing the metal layer comprises depositing the metal layer using atomic layer deposition, chemical vapor deposition or physical vapor deposition, and providing an oxide substrate.    USE - The process is useful for nucleating a metal film on a substrate.    ADVANTAGE - The process is capable of economically nucleating the metal film with high electrocatalytic activity, stability and electric conductivity.    DETAILED DESCRIPTION - The process comprises: providing a metal layer having a surface energy of greater than 2.5 J/m2; depositing a continuous, conformal layer of platinum or platinum alloy on the metal layer by hydrogen plasma assisted atomic layer deposition, where the layer of the platinum or platinum alloy has a thickness of less than 4 nm; and removing metal oxides from the metal layer. The step of providing the metal layer comprises depositing the metal layer using atomic layer deposition, chemical vapor deposition or physical vapor deposition, providing an oxide substrate, depositing a metal oxide layer by atomic layer deposition on the oxide substrate, and depositing the metal layer on the metal oxide layer. The deposition of the metal layer comprises depositing the metal layer using hydrogen plasma assisted atomic layer deposition. The step of removing metal oxides comprises exposing the metal layer to a hydrogen plasma.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a polymer electrolyte membrane fuel cell stack.    Proton exchange membrane (12)    Anode catalyst layer (14)    Cathode catalyst layer (16)    Anode diffusion layer (18)    Cathode diffusion layer. (20)