AVS 59th Annual International Symposium and Exhibition
    Surface Science Tuesday Sessions
       Session SS+NS-TuA

Paper SS+NS-TuA12
Structure and Electronic Properties of Ni Nanoparticles Supported on Reducible CeO2(111) Thin Films

Tuesday, October 30, 2012, 5:40 pm, Room 21

Session: Reactivity of Size and Shape Selected Nanoparticles
Presenter: J. Zhou, University of Wyoming
Authors: Y.H. Zhou, Xiamen University, Republic of China
J. Zhou, University of Wyoming
Correspondent: Click to Email
Ceria-supported Ni nanoparticles have been of great interest as ethanol and methane reforming catalysts for hydrogen production in fuel cell applications. Recent studies have indicated that the catalytic reactivity of these ceria-supported Ni nanoparticles can be influenced by the redox properties of ceria as well as the synergistic effect between the two. To elucidate the nature of their activity, we studied Ni particles deposited on fully oxidized CeO2(111) and reduced CeO1.88(111) thin films using scanning tunneling microscopy and x-ray photoelectron spectroscopy at the fundamental level. Ceria thin films were grown in situ on Ru(0001) under ultrahigh vacuum conditions. Ni was vapor-deposited onto ceria thin films. At 300 K, metallic Ni is the only species present on the reduced ceria. However, a small amount of Ni is oxidized to Ni2+ on CeO2. Oxidation of Ni on CeO2 can be facilitated by annealing as well as by depositing Ni at 500 K. Scanning tunneling microscopy studies show that Ni forms two-dimensional particles on ceria at room temperature, which suggests a strong Ni-ceria interaction. The particles can agglomerate into large three-dimensional structures with further heating. The structure and electronic properties of Ni metal particles on ceria were further compared to those of bimetallic Ni-Au and Ni-Rh particles.