关键词: 电化学扫描隧道显微镜, SO42-离子, 电沉积, 外延生长

Abstract: Metal thin films have attracted considerable interest in relation to catalysis, energy, material, corrosion and environmental protection. Pd thin film is capable of proton reduction and strong hydrogen absorption, which has shown electrocatalytic activity to the oxidation of small organic molecules. In this paper, in_situ STM measurements are performed to study the deposition process and the influence of the surface structure and anion adsorption. When Pd is deposited from PdSO4 solution on Au(111) in the UPD range, a monolayer of Pd with pseudomorphic (1×1) structure was formed on the substrate with induced (3×7) R19° SO2-4 adsorption. With decreasing potential the OPD range, the second pseudomorphic monolayer is formed with induced SO2-4 adsorption similar to that on the first monolayer. When the Pd reaches more than two monolayers, the deposition process changes to follow three_dimensional growth model with increased defects. Pd deposition from PdSO4 on Au (111) (1×1) follows the epitaxial way to form two complete monolayers of Pd film, in which induced anion adsorption on Pd film could play an important role.