Interaction between carbon disulfide and oxygen on a Ni(1 1 0) surface

Adsorption of CS2 as well as of mixtures of CS2 and O2 of varying compositions on a clean Ni(1 1 0) surface has been investigated using X-ray photoelectron spectroscopy. Pure CS2 adsorbs dissociatively giving rise to graphitic carbon (C1s, 285 eV), chemisorbed sulfur (S2p, 164 eV) and perhaps a small proportion of CS(a) (C1s, 286 eV). A CS2–O2 mixture dilute in oxygen (220:1) gives rise to COS(a) (O1s, 534 eV) due to the reaction between the O1−(s) and CS(s) transients. The COS(a) species is also formed in the case of a 15:1 CS2–O2 mixture, the other prominent surface species being O1−(a) (531 eV). When a mixture containing comparable proportions of CS2 and O2 (2:1) is dosed, mainly O2−(oxidic) species (O1s, 530 eV) is formed with no evidence for sulfur on the surface. When O2 and CS2 are dosed in a sequential manner, there is some formation of COS(a). On the other hand, when O2 is dosed on a surface predosed with CS2, adsorption of oxygen is inhibited.