CO oxidation on inverse Ce6O12/Cu(111) catalyst: role of copper-ceria interactions.

The surface structures, O2 adsorption, and CO oxidation reaction properties of Ce6O12/Cu(111) have been investigated using density functional theory including on-site Coulomb corrections (DFT + U). Results show that the supported ceria nanoparticles would gain electrons from the Cu(111) surface, and the Ce4+ are reduced to Ce3+. In addition, the oxygens at the interface have been largely activated, resulting in much low formation energy of O vacancies. For the CO oxidation reaction, two possible pathways are investigated, CO reacts with the O2 molecule adsorbed on Ce3+ and the lattice O at the interface, respectively. It has been found that CO reacting with the lattice O atom gives a lower reaction barrier than that of adsorbed O2 on Ce3+. These results are important for further understanding of the role of different active sites on the inverse CeOx/Cu(111) surface structure.