Studies of Electrodeposition of Silver on an Iodine-Pretreated Stepped Surface: Pt(S)(6(111)x(111))

摘要

Layers of Ag electrodeposited from aqueous solution onto a Pt(S)6(111)x(111)(3xT)-1 adlattice formed by pretreatment of the Pt(S)6(111)x(111) surface with I2 vapor were studied by LEED, AES and thermal desorption, Stability of the I adlattice toward exposure to perchloric acid solution, and persistence of I on the surface during multiple cycles of electrodeposition and dissolution of Ag was demonstrated. The I adlattice served to protect the Pt and Ag electrodeposited surfaces from unwanted side reactions. Electrodeposition of Ag occurred in three well-resolved UPD regions. Subsequent UHV experiments, after each UPD peak and up to coverages of a few monolayers, revealed that stable and ordered Ag superlattices were formed, each UPD region leading to a change in LEED pattern and superlattice structure. These results are compared with previous results for smooth Pt(111), evealing clues as to the role of steps in electrodeposition.