Adsorption and Surface Reaction of SO2 on Cu(100) Studied by S K-Edge XAFS and STM

Abstract. Adsolption and reaction of SO2 on Cu(100) at room temperature has been studied by means of S K-edge XAFS, AES, LEED, XPS and STM. It has been revealed that there are atomic S and SO3 with the stoichiometric ratio of 1:2 on the surface. This indicates that a disproportionation reaction of 3SOz(a)+S(a)+2S03(a) occurs at room temperature. The atomic S locates in the fourfold hollow site. SO3 adsorbs with its trigonal pyramid upright on the surface. The (2x2) and ~(4x6) domains were observed by STM. The former contains only one SO3 species in the unit cell without atomic S, while the latter involves one SO3 and two atomic S. This implies the occurrence of drastic migration of resultant products. 1