Initial stages of Pd deposition on Au( hkl) : Part II: Pd on Au(100)

• Published in: Surface science Vol. 461; no. 1; pp. 155 - 167
• Main Authors: Kibler, L.A., Kleinert, M., Kolb, D.M.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.08.2000; Amsterdam Elsevier Science; New York, NY
• Subjects: Adsorption; Chemistry; Electrochemical methods; Electrochemistry; Exact sciences and technology; General and physical chemistry; Gold; Growth; Metal–electrolyte interfaces; Palladium; Scanning tunneling microscopy; Single crystal surfaces; Study of interfaces; Surface structure, morphology, roughness, and topography; Gold; Scanning tunneling microscopy; Metal–electrolyte interfaces; Growth; Electrochemical methods; Palladium; Single crystal surfaces; Surface structure, morphology, roughness, and topography; Cyclic voltammetry; Adsorption; Growth mechanism; Electrode electrolyte interface; Transition metal; Experimental study; STM; Island structure; Surface structure
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(00)00569-0

The deposition of Pd onto unreconstructed Au(100) was studied by in situ scanning tunnelling microscopy and cyclic voltammetry for both an island-free surface and one covered with islands that originate from lifting of the (hex)-reconstruction. On the bare Au(100) surfaces, a (3× 10 )-structure of adsorbed [PdCl 4] 2− with atomically resolved images of the ligand atoms was observed. An equivalent of about one Pd monolayer is deposited at underpotentials on Au(100). On top of the resulting layer a distorted-hexagon chloride adlayer is formed. The growth mechanism for Pd on island-covered Au(100) is markedly different from that for the island-free surface. In the overpotential region, Pd films grow epitaxially with a slightly increased step density at higher coverage. These thicker Pd overlayers behave very similar to surfaces of massive Pd(100) single crystals, whereas the first Pd layers on Au(100) have a clearly different electrochemical behaviour. The presence of small Au islands after dissolution of Pd points towards surface alloy formation in the underpotential region.