Hydrohalic acid anion interaction with silver surfaces: Ag(111) – iodide
In this chapter the experimental results on adsorption of iodide interaction on Ag(111) surface is described.
CV and STM reveal that on Ag(111), iodide forms a (√3 × √3)R30° before and a (8 × 8) structure after a sharp CV peak at ~−0.2 V (SCE) in 5 × 10−4 KI + 0.15 M NaOH solution, the latter being most likely a higher-commensurate compound overlayer.
Cyclic voltammetry indicates iodide adsorption/desorption in the range −0.8 V to −0.6 V (Ag/AgCl) and a phase transition at −0.05 V, i.e., formation of bulk AgI, in 0.1 mM HI + 0.1 mM KI, buffered with KF-KOH at pH 10.
Also a continuous structural compression of the I-lattice from the (√3 × √3R–30°) via a (√3qRβ × √3)R30° to the (√3 × √3)R30° followed by an abrupt phase transition into a rotated hexagonal (√3r × √3r)R(30° + α) structure with increasing potential has been described on the basis of in situ STM and ex situ LEED studies. The latter phase is attributed to a Moiré superstructure [1, 2, 3].
scanning tunneling microscopy
saturated calomel electrode
low-energy electron diffraction