Abstract
Adsorption of the methoxy radical on clean and on low oxygen precovered Ru(0 0 0 1) metallic surfaces has been studied by density-functional theory cluster calculations. Methoxy is predicted to be preferentially chemisorbed on both hollow sites (hcp and fcc) of such surfaces, and adopts an upright orientation ( C 3 ν local symmetry). Such prediction is supported by the good agreement found between the calculated vibrational frequencies and the experimentally observed RAIRS spectra. Regarding the charge transfer process between the adsorbate and the surface, our results suggest that the bonding is dominantly polar covalent which arises from a charge donation from the ruthenium surface to the radical, and the co-adsorbed electronegative oxygens deplete slightly the surface electron density. However, the major difference is not induced through much O–Ru bonding, but indirectly, by lowering the valence d-band center of the system. This results in a lower adsorption energy for methoxy than on the clean Ru(0 0 0 1) surface, in accordance with experimental data. Further, accordingly to the present calculations, the radical is expected to dissociate or desorb more easily on the modified surface but with no participation from the co-adsorbed oxygen atoms.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
