Pseudomorphic growth of Pd monolayer on Au(111) electrode surface

The surface structure of a Pd layer electrochemically deposited onto Au(111) from PdCl2−4 solution has been studied by surface X-ray diffraction. By combining the measurements of the specular and non-specular rod profiles, both in-plane and out-of-plane structures have been determined. On the Au(111) electrode surface, Pd occupies the cubic closest packing site and forms a pseudomorphic smooth monolayer. The formation of the stable Pd overlayer is explained by the lifting of the surface reconstruction of the Au substrate. The PdAu bond length at the Pd/Au(111) interface has been found to be 2.82 Å, which is close to the sum of the atomic radii of Pd and Au in each bulk.