AVS 49th International Symposium
    Surface Science Wednesday Sessions
       Session SS2-WeA

Paper SS2-WeA4
Structural Studies of Ti/Pt(111) Surfaces

Wednesday, November 6, 2002, 3:00 pm, Room C-110

Session: Structure and Chemistry at Metal Surfaces
Presenter: S. Hsieh, University of Southern California
Authors: S. Hsieh, University of Southern California
T. Matsumoto, University of Southern California
J. Kim, University of Southern California
B.E. Koel, University of Southern California
Correspondent: Click to Email
Alloys of platinum and a second metal component are of increasing interest for a number of applications. Structural studies have been carried out for bimetallic surfaces with Pt alloyed with many transition metals and main group metals. In this work, we have used He @super+@-ion scattering (He@super+@-ISS), X-ray photoelectron spectroscopy (XPS), and low energy diffraction (LEED) to determine the structure of ordered Ti/Pt(111) surface alloys formed by depositing ultrathin Ti films on Pt(111) and annealing to different temperatures up to 1100 K. The Ti film coverage was determined by He@super+@-ISS. No LEED pattern was observed at room temperature immediately after Ti deposition. At 800 K, Ti started to alloy with Pt and formed a (6x @sr@43) structure in LEED that grew sharper as the temperature was increased to 1000 K. A weak (2 x 2) pattern was observed for Ti coverages larger than 1 monolayer, but this structure was less stable and disappeared at high temperature leaving only the (6x @sr@43) pattern. XPS showed that the Ti core level spectra shifted by 2.0 eV upon alloying compared to that from a thick Ti film. Observation and further characterization of the new Ti/Pt(111)-(6x @sr@43) surface structure should aid in understanding and tailoring chemical properties of practical catalysts.