Adsorbed CO induced change of the adsorption site and charge of Au adatoms on FeO(111)/Ru(0001)

A first principles study of the influence of CO adsorption on the charge state, adsorption site, and stability of Au adatoms on FeO/Ru(0001) was presented. Calculations were first carried out to explore the detailed interface structure of a bilayer FeO(111) film on Ru(0001). The HCP domain inside the Moire supercell has a rather small rumpling with both the Fe and 0 atoms directly bonded to the Ru substrate. The most stable adsorption of an Au atom on FeO/Ru(0001) is at the Fe-bridge site in the HCP domain, where Au binds with two flipped Fe atoms and is negatively charged. After exposure to CO, the Au anions at the Fe-bridge site changed their position to the O-top site by overcoming a small barrier of only 0.12 eV, where they formed stable Au+-CO species with a significant reduction in the formation energy. The results highlighted the importance of in situ characterization of supported catalysts under reaction conditions, and implications on catalyst stability were also discussed. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved