Size-dependent reactivity of self-organized nanostructured O/Cu(110) surfaces towards H2S

Scanning tunneling microscopy was used to study the reactivity of self-organized nanostructured O/Cu (110) surfaces towards H2S. We took advantage of the fast and easy nanostructuring process of the O/Cu (110) system to study in detail the reaction mechanisms on three structures having different width of CuO stripes. Detachment of Cu-O chains from CuO stripes occurred in all cases but the formation of S-c(2 x 2) islands was observed only on wider ( > 10 nm) CuO stripes. At low exposure, structures were observed at the CuO stripe edge. Linear structures, aligned along the [110] direction and showing 2 x periodicity, were also observed on copper stripes. The competition between detachment and c(2 x 2) island growth mechanism depends on the H2S adsorption rate. At higher pressure, it is shown that the sulfidation only proceeds by sulfur islands growth in wider CuO stripes. These results show that self-organized nanostructures on metal surfaces are powerful tools to study reactions at the nanometer scale and the relationship between local structure and reactivity. (C) 2016 Elsevier B.V. All rights reserved.