| AVS 56th International Symposium & Exhibition | |
| Surface Science | Monday Sessions |
| Session SS1-MoM |
| Session: | Vibrational Spectroscopy and Surface Reactions |
| Presenter: | M.S. Chen, Xiamen University, China |
| Authors: | M.S. Chen, Xiamen University, China X. Wang, Xiamen University, China H.L. Wan, Xiamen University, China |
| Correspondent: | Click to Email |
Previous we had found that CO oxidation on Pd-group metals at temperatures between 450 and 600 K and pressures between 1 and 300 Torr increases markedly with an increase in the O2/CO ratio above 0.5.[Surf. Sci. 2007,601, 5326.] The catalytic surfaces, formed at discrete O2/CO ratios > 0.5, exhibit rates 2 to 3 orders of magnitude greater than those rates observed for stoichiometric reaction conditions and similar reactant pressures or previously in ultrahigh vacuum studies at any reactant conditions and extrapolate to the collision limit of CO in the absence of mass transfer limitations. Here we used HREELS to address the relative activities of surface CO and oxygen species. The surface oxygen species can be removed by CO at room temperature and low pressure, 10-8 Torr. While a much higher oxygen pressure or above room temperature is required to remove surface adsorbed CO species. Furthermore, in-situ RAIRS and Raman spectroscopy were used to characterize this highly active surface formed at higher O2/CO ratios on Pd.