AVS 56th International Symposium & Exhibition
    Surface Science Thursday Sessions
       Session SS1-ThA

Paper SS1-ThA8
Nucleation and Growth of Ceria-supported Pt-Au Bimetallic Nanoparticles

Thursday, November 12, 2009, 4:20 pm, Room M

Session: Nucleation and Growth - Metals
Presenter: J. Zhou, University of Wyoming
Authors: Y. Zhou, University of Wyoming
J. Zhou, University of Wyoming
Correspondent: Click to Email
Ceria-supported metal particles have been under intensive study for their potential applications in fuel cells owing to the peculiar redox properties and oxygen storage capacity of ceria as well as the synergistic effect between the metal and ceria. Of particular interest are bimetallic systems because they can also exhibit unusual chemical and catalytic properties compared to the individual metals due to the synergistic effect between the two metals. To elucidate the nature of their chemistry in fuel cell applications, it is of significance to gain a fundamental understanding of their nucleation and growth processes on ceria supports. Here we report our recent study of bimetallic Pt-Au deposited on fully oxidized CeO2(111) and reduced CeOx(111) thin films using scanning tunneling microscopy and x-ray photoelectron spectroscopy. Ceria thin films with controlled degrees of cerium reduction were grown in situ on Ru(0001) under ultrahigh vacuum conditions. Pt and Au were vapor-deposited onto ceria thin films. Our study demonstrates that the growth and sintering behavior of Pt-Au bimetallic particles is dependent on the Ce oxidation states, metal compositions, as well as the metal deposition sequence. The growth of Pt-Au on well-ordered CeOx(111) thin films was compared to that of pure Pt and pure Au as well as to that of bimetallic Pt-Au supported on nanocrytalline ceria surfaces. The research is sponsored by the start-up fund at University of Wyoming and the Wyoming NASA Space grant.