4.3 Changes in Surface Stress during UPD
125
study [47] indicated that the oxidation state of the Cu species is approximately +
1, suggesting the formation of a surface dipole in which the Cu atom has a partial
positive charge, while the Au atom has a partial negative charge. The formation
of the surface dipoles may promote the adsorption of SO 4
2− on the Cu-(1 × 1)
monolayer/Au (111) electrode to decrease toward compressive direction.
Roles of Co-Adsorption of chloride Ions
Figure 4.12 shows (a) the cyclic voltammogram and (b) the vs. E curve measured
at a potential scan rate of 5 mV s
−1 for the (111)-textured Au thin-film (with a thickness of 220 nm) electrode in 0.1 M HClO 4 solution containing 10
−3 M Cu(ClO 4 ) 2
and 10
−3 M KClO 4 , free from SO 4
2− ions [19]. The cathodic charge density c =
−2.4 C m
−2 at 0.25 V (SHE) referred to c = 0 at 0.60 V (SHE), calculated from
Fig. 4.12 a Cyclic voltammogram and b the vs. E curve measured at a potential scan rate
of 5 mV s −1 for the (111)-textured Au thin-film (with a thickness of 220 nm) electrode in 0.1 M
HClO 4 solution containing 10 −3 M Cu(ClO 4 ) 2 and 10 −3 M KClO 4 free from SO 4
2− ions [19].
Reprinted from [19], Copyright 2007, with permission from Springer Nature