title: Multiple Coordination of CO on Molybdenum Nanoparticles: Evidence for Intermediate Mox(CO)y Species by XPS and UPS.
abstract: CO chemisorption on the metallic molybdenum nanoparticles supported on the thin alumina film was investigated by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). A binary compound of molybdenum and CO is found to be formed on the surface upon CO dose, accompanied with a positive binding energy shift of the Mo 3d doublet and a localized Mo 4d valence band. A loose packing of the metallic molybdenum favors the formation of this intermediate Mox(CO)y species. The formation of the Mox(CO)y species implies that the property of the metallic molybdenum nanoparticles on the thin alumina film is much different from that of the bulk molybdenum, indicating a significant nanometer size effect.
authors.affiliation: State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Jiang
authors.forename: Weixin
authors.initials: W
authors.lastname: Huang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Dali
authors.initials: D
authors.lastname: Tan
authors.forename: Xinhe
authors.initials: X
authors.lastname: Bao