Adsorption and reaction of sulfur dioxide with Cu(110) and Cu(110)-p(2×1)-O.

On Cu(110)-p(2×1)-O at 300 K SO[sub 2](g) reacts stoichiometrically with O(a) to form a surface covered with both c(4×2)-SO[sub 3] and p(2×2)-SO[sub 3] structures. With heating SO[sub 2](g) evolves from the surface in distinct reaction-limited states at 384 K, 425 K, and 470 K, and the surface reverts to its initially oxidized state. On Cu(110), SO[sub 2](g) adsorbs molecularly below 300 K; upon annealing to 300 K, the sulfur dioxide disproportionates according to 3SO[sub 2](a)→S(a)+2SO[sub 3](a) with concomitant desorption of excess SO[sub 2](a). The surface formed in this manner exhibits large c(2×2)-S domains which encompass scattered c(4×2)-SO[sub 3] and p(2×2)-SO[sub 3] structures in a 1:2 coverage ratio. After being annealed to 400 K, the surface exhibits large p(2×2)-SO[sub 3] domains surrounding smaller c(4×2)-SO[sub 3] and c(2×2)-S islands. Continued heating past 400 K results in decomposition of sulfite according to SO[sub 3](a)→SO[sub 2](g)+O(a), evolving sulfur dioxide at 470 K and leaving the surface covered with atomic sulfur and oxygen. Real-time STM images show the mobility of oxygen at island boundaries and the mobility of sulfite amid the p(2×1)-O structures. STM measurements suggest that the sulfite occupy four-fold hollow sites. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]