AVS 53rd International Symposium
    Surface Science Friday Sessions
       Session SS-FrM

Paper SS-FrM2
First Principles Studies of CO Adsorption and Oxidation on Cu2O(100)*

Friday, November 17, 2006, 8:20 am, Room 2002

Session: Oxide Surfaces and Interfaces
Presenter: T. Rahman, Kansas State University
Authors: S. Stolbov, Kansas State University
D. Le, Kansas State University
T. Rahman, Kansas State University
Correspondent: Click to Email
Recent experimental findings@footnote 1@ indicate that the rate of CO oxidation on Cu2O surface is much higher than that on Cu and CuO surfaces. This result is also in qualitative agreement with results on copper oxide nanoparticles. To gain insight into the factors controlling the reactivity of oxide surfaces, we have examined from first principles the energetics of adsorption and oxidation of CO on Cu2O(100). Calculations are based on density functional theory using the generalized gradient approximation for the electron exchange-correlation term. Furthermore, we obtain the pressure/temperature (p,T) surface phase diagram by applying the ab initio thermodynamics approach@footnote 2@ to the surface in contact with gaseous O2. We find that the O-termination of Cu2O(100) is preferred for all reasonable range of temperature and O2 pressure. We also find that CO molecules which chemisorb on the surface O, directly associate with it to form CO2 without any activation barrier. On the other hand, CO molecules which adsorb on a surface Cu atom are found to slide first towards the neighboring O atom to form CO2. We analyze the local densities of electronic states and valence charge densities of the systems to rationalize the results. @FootnoteText@ @footnote 1@T.-J. Huang and D.-H. Tsai, Catal. Lett. 87, 173 (2003). @footnote 2@K. Reuter and M. Scheffler, Phys. Rev. B 65, 035406 (2002). * Work supported in part by DOE under grant No. DE-FG02-03ER15465 and computational resources provided by NSF Cyberinfrastructure and TeraGrid grant No; DMR050039N.