AVS 52nd International Symposium
    Surface Science Wednesday Sessions
       Session SS2-WeA

Paper SS2-WeA2
Probing the Chemical Reactivity of Oxide-Supported Pd Nanoparticles with STM

Wednesday, November 2, 2005, 2:20 pm, Room 203

Session: Reactions on Nanoclusters
Presenter: A.P. Baddorf, Oak Ridge National Laboratory
Authors: J. Zhou, Oak Ridge National Laboratory
A.P. Baddorf, Oak Ridge National Laboratory
S.V. Kalinin, Oak Ridge National Laboratory
S.H. Overbury, Oak Ridge National Laboratory
D.R. Mullins, Oak Ridge National Laboratory
Correspondent: Click to Email
Oxide-supported metal nanoparticles play a central role in current heterogeneous catalysis. They may exhibit unique catalytic properties that can be tuned by particle size and structure as well as by choice of oxide substrate. However, there is still a need to understand the origins of catalytic activity of metal/metal-oxide interfaces at the atomic scale. We report scanning tunneling microscopy (STM) studies of supported Pd nanoparticles evaporated on a rutile TiO@sub 2@ (110) single crystal surface in ultrahigh vacuum as a model catalytic system. A range of particle sizes with narrow size distributions was prepared by varying Pd coverage, substrate growth and post-annealing temperatures. Electronic properties of the particles and adjacent substrate were determined with I-V and dI/dV spectroscopies. The surface chemistry of supported Pd particles was explored for reactive gases such as O@sub 2@, CO and benzene between 20 and 300 K. Images of specific particles are compared before and after in situ exposures. Research was sponsored by the Laboratory Directed Research and Development Program of ORNL, managed by UT-Battelle, LLC for the U. S. DOE under Contract DE-AC05-00OR22725.