Abstract
Auger electron spectroscopy (AES) and high-resolution electron energy loss spectroscopy (HREELS) showed that hydrogen reduction at 700 °K of a 120-Å nickel film deposited on TiO2 results in the segregation of TiOx (x close to 1) onto the nickel surface. Titanium oxide appears to diffuse rapidly through nickel. Room-temperature CO uptake was found to decrease with increasing surface titanium oxide concentration. HREELS showed that the concentration of bridge-bonded CO relative to on-top CO after room-temperature CO exposure decreases with increasing titanium oxide coverage on nickel. A site giving rise to a CO stretching frequency of 1850 cm-1 was found to survive after extended reduction. This was attributed to a site near the surface titanium oxide on nickel. The present study suggests that both physical coverage of the nickel surface by TiOx and the chemical interaction between nickel and TiOx on the surface are involved in SMSI.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 75-83 |
| Number of pages | 9 |
| Journal | Journal of Catalysis |
| Volume | 90 |
| Issue number | 1 |
| DOIs | |
| State | Published - Nov 1984 |
Funding
Acknowledgment is made to the Donors of the Petroleum Research Fund, administered by the American Chemical Society, for support of this research. Some parts of this research were carried out in the Surface Science Facility of Northwestern University Materials Research Center which is supported by the National Science Foundation MRL Program DMR 82-16972. We thank Professor W. M. H. Sachtler for many illuminating discussions and for communicating to us Refs. (32) and (33) prior to their publication.
ASJC Scopus subject areas
- Catalysis
- Physical and Theoretical Chemistry