Di. Sayago et al., Adsorption and desorption of SO2 on the TiO2(110)-(1X1) surface: A photoemission study - art. no. 205402, PHYS REV B, 6420(20), 2001, pp. 5402
By means of synchrotron radiation photoemission spectroscopy, we have inves
tigated the adsorption and desorption processes of the SO2 molecule on a ru
tile TiO2(110)-(1 X 1) surface. We have recorded the S 2p core-level photoe
mission peaks for different SO2 exposures at a substrate temperature of 120
K in order to get information about the divers species formed on the surfa
ce. We have also recorded real-time photoemission spectra to study the adso
rption from the early stages to large exposures and to follow the chemical
transformations occurring with the adsorbed species as the temperature incr
eases. We have seen that the first arriving molecules react with the oxygen
atoms of the surface forming SOx species, both at low and room temperature
. Doses higher than the saturation dose (6 L) lead to the dissociation of t
he molecule generating adsorbed S. SO2 multilayer has been found for exposu
res higher than around 250 L. We have found a progressive reduction of the
SOx species with the temperature and the formation of sulphide as the most
stable phase. We have not found any signature of molecular ordered species
at the interface.