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 CeO_x/Cu(111) surface structure.