G. Andreasen et al., Influence of the electric potential on the structure of pyridine adlayers on Au(111) terraces from in-situ scanning tunnelling microscopy imaging, J ELEC CHEM, 467(1-2), 1999, pp. 230-237
The adsorption and desorption of pyridine (Py) adlayers prepared on Au(111)
terraces were studied by in-situ scanning tunnelling microscopy (STM) and
conventional voltammetry using an aqueous 0.1 M HClO4 + 10(-4) M Py solutio
n at 298 K. The applied potential covered the range 0.15 V < E < 1.2 V (vs.
SHE), i.e. potentials above and below E-pzc, the potential of zero charge
of Au(111). In the range E-pzc < E < 0.96 V, hexagonal (4 x 4) ordered doma
ins corresponding to Py molecules adsorbed vertically on the Au(111) surfac
e coexist with disordered adlayer domains, but for E < E-pzc, the ordered a
dlayer structure disappears leaving uncovered Au(111) domains. Similarly, f
or E > 0.96 V, the (4 x 4) adlayer lattice is removed completely leading to
a bare Au(111) surface. By stepping E backwards to a value in the range E-
pzc < E < 0.96 V, the readsorption of Py takes place and the (4 x 4) adlaye
r domains are recovered in a few minutes. STM data offer the possibility of
discussing anion adsorption and the early electroformation stages of the O
H-containing adlayer on Au(111) terraces. (C) 1999 Elsevier Science S.A. Al
l rights reserved.