Formation of interfacial nano-layers in the system Pt–Ni–O

Solid state electrochemical cells have been applied to oxidize Pt–Ni alloys and NiO in contact with Pt. The resulting interfaces have been analyzed by analytical transmission electron microscopy. Highly oxidized phases and complex morphologies have been identified on a nanometer scale in both cases. These phenomena are discussed in the context of solid state pattern formation and characteristic reactions of the system Pt–Ni–O, such as alloy oxidation and reactions between NiO and Pt. Reaction and diffusion mechanisms, which can explain the formation of the complex microstructures, are introduced for each case.