Direct visualization of quasi-ordered oxygen chain structures on Au(110)-(1 x 2)

SURFACE SCIENCE

卷:650

Article

Hiebel, F.¹  Montemore, M. M.^1,2  Kaxiras, E.^2,3  Friend, C. M.^1,2 

[1] Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA

[2] Harvard Univ, Sch Engn & Appl Sci, Cambridge, MA 02138 USA

[3] Harvard Univ, Dept Phys, Cambridge, MA 02138 USA

关键词: Au(110);    Scanning tunneling microscopy;    Density functional calculations;    Oxygen;    Ordering;   

DOI  :  10.1016/j.susc.2015.09.018

来源: Elsevier

【 摘 要 】

The Au(110) surface offers unique advantages for atomically-resolved model studies of catalytic oxidation processes on gold. We investigate the adsorption of oxygen on Au(110) using a combination of scanning tunneling microscopy (STM) and density functional theory (DFT) methods. We identify the typical (empty-states) STM contrast resulting from adsorbed oxygen as atomic-sized dark features of electronic origin. DFT-based image simulations confirm that chemisorbed oxygen is generally detected indirectly, from the binding -induced electronic structure modification of gold. STM images show that adsorption occurs without affecting the general structure of the pristine Au(110) missing-row reconstruction. The tendency to form one-dimensional structures is observed already at low coverage (<0.05 ML), with oxygen adsorbing on alternate sides of the reconstruction ridges. Consistently, calculations yield preferred adsorption on the (111) facets of the reconstruction, on a 3-fold coordination site, with increased stability when adsorbed in chains. Gold atoms with two oxygen neighbors exhibit enhanced electronic hybridization with the O states. Finally, the species observed are reactive to CO oxidation at 200 K and desorption of CO2 leaves a clean and ordered gold surface. (C) 2015 Elsevier B.V. All rights reserved,

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