Complex reactions on a convertible catalyst surface: A study of the S-O-Cu system

SURFACE SCIENCE

卷:678

Article

Duerrbeck, S.^1,2  Shi, X. -R.³  Samadashvili, M.²  Redinger, J.⁴  Bertel, E.¹  Salmeron, M.² 

[1] Univ Innsbruck, Inst Phys Chem, Innsbruck, Austria

[2] Lawrence Berkeley Lab, Berkeley, CA 94704 USA

[3] Shanghai Univ Engn Sci, Coll Mat Engn, Shanghai 201620, Peoples R China

[4] Vienna Univ Technol, Dept Appl Phys, Vienna, Austria

关键词: Catalysis;    Sulphur;    Copper;    Scanning tunnelling microscopy;    Density functional theory;   

DOI  :  10.1016/j.susc.2018.03.010

来源: Elsevier

【 摘 要 】

The interaction of clean and partially oxidized Cu(110) with sulphur was studied by scanning tunneling microscopy and density functional theory calculations in the low-coverage range. On the clean Cu surface individual S atoms adsorb in the troughs between the Cu atom rows. Hollow sites are preferred, but long-bridge sites are occasionally occupied as well. The majority of adsorbed S, however, seems to be involved in the formation of highly mobile CuxSy clusters of various sizes. The clusters preferentially attach to steps thus changing the step morphology completely. Some of the clusters form aggregates on the terraces. On the partially oxidized surface similar clusters form and cause long-range mass transport to steps. Additionally, nanowires form in [001] direction on and along the surface oxide stress domains. These nanowires have a complex composition, exhibit different corrugations and appear sometimes as three-dimensional needles. Occasionally they flip their direction by 90 degrees, but doing so they partially decompose. Finally, annealing of the S-O-Cu surface leads to consumption of the surface oxide stripes indicating loss of oxygen presumably via SO2 formation. Simultaneously, linear sulphur chains suspended between the [001]-O-Cu-O-chains form in [1 (1) over bar0] direction. The surprising multitude of processes and products even at low-pressure, low-temperature conditions in the comparatively simple S-O-Cu system highlights the difficulty of controlling reactivity and selectivity on such convertible catalyst surfaces.

【 授权许可】

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