12252 J. Phys. Chem. B, Vol. 106, No. 47, 2002
Nicic et al.
occur in parallel). In addition, the formation of these ordered
phases might be kinetically slow. It is likely that the thermo-
dynamically favored structure is the pseudomorphic (1 × 1)
phase observed by both Sorensen et al. and Hayden et al. Mass
change data show that the second UPD stripping peak corre-
sponds to a mass change of about 15 ng (Figure 6, right-hand
trace).
References and Notes
(
1) Sapp, S. A.; Lakshmi, B. B.; Martin, C. R. AdV. Mater. 1999, 11,
4
02.
(2) Stickney, J. L. Electroanal. Chem. 1999, 21, 75.
3) Shannon, C.; Gichuhi, A.; Barnes, P. A.; Bozack, M. J. Proc.
Electrochem. Soc. 1999, 99-9, 282.
4) (a) Feliu, J. M.; Llorca, M. J.; Gomez, R.; Aldaz, A. Surf. Sci.
(
(
1993, 297, 209. (b) Herrero, E.; Rodes, A.; Perez, J. M.; Feliu, J. M.; Aldaz,
A. J. Electroanal. Chem. 1996 412 165. (c) Herrero, E.; Llorca, M. J.; Feliu,
J. M.; Aldaz, A. J. Electroanal. Chem. 1995, 383 145. (d) Gregory, B. W.;
Norton, M. L.; Stickney, J. L. J. Electroanal. Chem. 1990, 293, 85. (e)
Suggs, D. W.; Stickney, J. L. J. Phys. Chem. 1991, 95, 10056. (f) Yagi, I.;
Lantz, J. M.; Nakabayashi, S.; Corn, R. M.; Uosaki, K. J. Electroanal. Chem.
Finally, the sluggish stripping kinetics reflects the fact that
the half reaction is termolecular; that is, an adsorbed Te atom
+
must combine with two H2O molecules to form HTeO2 .
Nevertheless, both of these processes are rapid on the time scale
of the linear potential sweep used in our CV and EQCM
experiments. Thus, the large peak separation between the
deposition and stripping peaks appears not to be a kinetic
overpotential but to reflect the energetics of Te nucleation on
Au surfaces.
1
996, 401, 95. (g) Yagi, I.; Nakabayashi, S.; Uosaki, K. Surf. Sci. 1998,
406, 1. (h) Suggs, D. W.; Stickney, J. L. Surf. Sci. 1993, 290 375. (i)
Ikemiya, N.; Yamada, K.; Hara, S. J. Vac. Sci. Technol. 1996, B14, 1369.
(j) Ikemiya, N.; Iwai, D.; Yamada, K.; Vidu, R.; Hara, S. Surf. Sci. 1996,
3
69, 199. (k) Sorenson, T. A.; Lister, T. E.; Huang, B. M.; Stickney, J. L.
J. Electrochem. Soc. 1999, 146, 1019.
5) Sorenson, T. A.; Varazo, K.; Suggs, D. W.; Stickney, J. L. Surf.
Sci. 2001, 470, 197.
6) Yagi, I.; Nakabayashi, S.; Uosaki, K. J. Phys. Chem. B 1998, 102,
677.
7) Hayden, B. E.; Nandhakumar, I. S. J. Phys. Chem. B 1997, 101,
7751.
(
(
Conclusions
2
(
We have characterized the UPD of Te on Au(111) surfaces
using chronocoulometry and EQCM. Our results demonstrate
unambiguously that the first UPD peak corresponds to the
(
(
8) Sauerbrey, G. Z. Phys. 1959, 155, 206.
9) (a) Bosco, E.; Rangarajan, S. K. J. Chem. Soc., Faraday Trans. 1
1981, 77, 1673. (b) Bosco, E.; Rangarajan, S. K. J. Electroanal. Chem.
+
reduction of a preadsorbed layer of HTeO2 to form Te and
1981, 129, 25. (c) Bhattacharjee, B.; Rangarajan, S. K. J. Electroanal. Chem.
1991, 302, 207.
that the second UPD peak corresponds to the reduction of
+
(10) Budevski, E. B. In ComprehensiVe Treatise of Electrochemistry;
Conway, B. E., Bockris, J. O’M., Yeager, E., Kahn, S. U. M., White, R.
E., Eds.; Plenum Press: New York, 1983; Vol. 7, pp 399-450.
HTeO2 from solution. In both cases, the half reaction appears
+
to be the four-electron reduction of HTeO2 to Te.
(11) (a) Bewick, A.; Fleischmann, M.; Thirsk, H. R. Trans. Faraday
Soc. 1962, 58, 2200. (b) Fleischmann, M.; Thirsk, H. R. In AdVances in
Electrochemistry and Electrochemical Engineering; Delahay, P., Tobias,
C. W., Eds.; Wiley Interscience: New York, 1963; Vol. 3, p 123.
Acknowledgment. C.S. and I.N. acknowledge the financial
support of the Petroleum Research Fund, the U.S. Department
of Energy and the National Science Foundation. U.D. acknowl-
edges the financial support of TUBITAK, the National Science
Foundation of Turkey.
(
12) Lepiller, C.; Cowache, P.; Guillemoles, J. F.; Gibson, N.; Ozsan,
E.; Lincot, D. Thin Solid Films 2000, 361, 118.
13) Thus, we cannot rule out a possibility such as HTeO2 (ads) + 4e
+
-
(
+
+ 3H ) ) ) Te(ads) + 2H2O(ads).