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T. Fujitani et al. / Surface Science 601 (2007) 1615–1622
atomic sulfur with oxygen over Ir and Rh may be due to
different processes of formation of atomic sulfur from SO2.
References
[1] M. Ogura, A. Kawamura, M. Matsukata, E. Kikuchi, Chem. Lett. 29
(2000) 146.
[2] T. Yoshinari, K. Sato, M. Haneda, Y. Kintaichi, H. Hamada, Catal.
Commun. 2 (2001) 151.
4. Conclusions
[3] T. Yoshinari, K. Sato, M. Haneda, Y. Kintaichi, H. Hamada, Appl.
Catal. B 41 (2003) 157.
(1) SO2 was molecularly adsorbed on the Ir(111) surface
at 200 K. The adsorbed SO2 disproportionated to
atomic sulfur and SO3 at 300 K. Only atomic sulfur
was present on the Ir(111) surface above 500 K.
[4] M. Haneda, Pusparatu, Y. Kintaichi, I. Nakamura, M. Sasaki, T.
Fujitani, H. Hamada, J. Catal. 229 (2005) 197.
[5] G.J. Jackson, S.M. Driver, D.P. Woodruff, N. Abrams, R.G. Jones,
M.T. Butterfield, M.D. Crapper, B.C.C. Cowie, V. Formoso, Surf.
Sci. 459 (2000) 231.
[6] A.R. Alemozafar, X.C. Guo, R.J. Madix, J. Chem. Phys. 116 (2002)
4698.
[7] A.R. Alemozafar, X.C. Guo, R.J. Madix, Surf. Sci. 524 (2003) L84.
[8] A.R. Alemozafar, X.C. Guo, R.J. Madix, Surf. Sci. 526 (2003) L127.
p
p
( 3 · 3)R30ꢁ-ordered surface structures due to
atomic sulfur were observed at 500 K.
(2) SO2 was molecularly adsorbed on the Rh(111) sur-
face at 200 K. The adsorbed SO2 dissociated to atomic
sulfur and oxygen above 250 K. Atomic sulfur and a
small amount of atomic oxygen were present on
surfaces above 500 K. The adsorption structure of
[9] G.J. Jackson, J. Ludecke, S.M. Driver, D.P. Woodruff, R.G. Jones,
¨
A. Chan, B.C.C. Cowie, Surf. Sci. 389 (1997) 223.
[10] L. Wilde, M. Policik, J. Haase, B. Brena, D. Coccocˇ, G. Comelli, G.
Paolucci, Surf. Sci. 405 (2003) 215.
[11] G.J. Jackson, D.P. Woodruff, A.S.Y. Chan, R.G. Jones, B.C.C.
Cowie, Surf. Sci. 577 (2005) 31.
p
p
atomic sulfur was transformed from ( 3 · 3)R30ꢁ
below 400 K to random above 500 K.
(3) For Ir(111), adsorption of NO on hollow sites was
selectively inhibited in the presence of atomic sulfur,
because atomic sulfur was adsorbed only on hollow
sites. In contrast, NO adsorption and CO adsorption
on Rh(111) were uniformly inhibited by randomly
adsorbed atomic sulfur.
´
[12] A. Gutierrez-Sosa, J.F. Walsh, C.A. Muryn, P. Finetti, G. Thornton,
A.W. Robinson, S. D’Addato, S.P. Frigo, Surf. Sci. 364 (1996) L519.
[13] P.-T. Howe, H.-L. Dai, Surf. Sci. 451 (2000) 12.
[14] P. Zebisch, M. Stichler, P. Trischberger, M. Weinelt, H.-P. Steinruck,
¨
Surf. Sci. 371 (1997) 235.
[15] K. Wilson, C. Hardacre, C.J. Baddeley, J. Ludecke, D.P. Woodruff,
¨
(4) Atomic sulfur readily reacted with surface oxygen
and was completely removed from the Ir(111) sur-
face, whereas atomic sulfur did not react with oxygen
on Rh(111). Thus, the reactivity of atomic sulfur
with oxygen was significantly higher on Ir(111) than
on Rh(111).
R.M. Lambert, Surf. Sci. 372 (1997) 279.
[16] M. Polcˇik, L. Wilde, J. Haase, B. Brena, G. Comelli, G. Paolucci,
Surf. Sci. 381 (1997) L568.
[17] J. Kro¨ger, J. Kuntze, A. Atrei, B. Cortigiani, U. Bardi, G. Rovida,
Surf. Sci. 539 (2003) 537.
[18] Ts. Marinova, K.L. Kostov, Surf. Sci. 185 (1987) 203.
[19] X. Xu, C.M. Friend, J. Am. Chem. Soc. 113 (1991) 6779.
[20] T. Fujitani, I. Nakamura, Y. Kobayashi, A. Takahashi, M. Haneda,
H. Hamada, J. Phys. Chem. B 109 (2005) 17603.
[21] S. Eck, C. Castellarin-Cudia, S. Surnev, K.C. Prince, M.G. Ramsey,
F.P. Netzer, Surf. Sci. 536 (2003) 166.
Acknowledgement
This work was supported by the Japan Society for the
Promotion of Science (JSPS-KAKENHI 17350079).
[22] I. Nakamura, Y. Kobayashi, H. Hamada, T. Fujitani, Surf. Sci. 600
(2006) 3235.