| AVS 55th International Symposium & Exhibition | |
| Surface Science | Wednesday Sessions |
| Session SS1-WeA |
| Session: | Structure of Oxide Surfaces and Oxide Heterostructures |
| Presenter: | J.B. Park, Brookhaven National Laboratory |
| Authors: | J.B. Park, Brookhaven National Laboratory D.J. Stacchiola, Brookhaven National Laboratory J. Graciani, Brookhaven National Laboratory S. Ma, Brookhaven National Laboratory A. Nambu, Brookhaven National Laboratory J.F. Sanz, Universidad de Sevilla, Spain J.A. Rodriguez, Brookhaven National Laboratory J. Hrbek, Brookhaven National Laboratory |
| Correspondent: | Click to Email |
Catalysts containing nanoparticles of ceria supported on titania exhibit a high activity for the water-gas shift reaction and the CO oxidation. It has been suggested that this catalytic activity is related to the easy reversible change of the oxidation states of ceria (Ce3+ and Ce4+), but very little is known about the ceria-titania interactions and the growth mode of ceria on titania. In this work, the growth of CeOx on rutile TiO2 (110) have been investigated by STM and PES in UHV. The deposition of CeOx changes the morphology of TiO2 (110), creating several layers deep steps. At low coverages (less than 0.3ML of Ce), CeOx nanoclusters are preferentially nucleated on the in-plane oxygen atoms of TiO2 (110) and exhibit diagonal arrays along the [001] direction by sharing bridging oxygens. At high coverages, extended rectangular islands of CeOx are observed. XPS studies show that the diagonal arrays of CeOx nanoclusters and their coverage-dependent morphological changes are associated with changes in the oxidation states of the CeOx nanoparticles. The DFT calculations provide the detailed atomic structures for CeOx on rutile TiO2 (110).
This research was carried out at Brookhaven National Laboratory and supported by the US Department of Energy (Chemical Sciences Division, DE-AC02-98CH10886).