Dealloying of Cu₃Pt (111) Studied by Surface X-ray Scattering

The structural evolution during dissolution of Cu from Cu₃Pt (111) single crystal surfaces under potential control has been studied by X-ray scattering. An epitaxial, compressively strained, Pt-rich overlayer is formed upon Cu dissolution and thickens as the potential increases (more anodic). The compressive lattice strain in the Pt-rich overlayers decreases as the potential and overlayer thickness increase. The Pt-rich overlayers exhibit same fcc stacking sequence as the substrate. We compare and contrast the behavior of the dealloyed single crystals with similarly dealloyed Cu₃Pt thin films and nanoparticles.