Direct CO Oxidation by Lattice Oxygen on Zr-Doped Ceria Surfaces

Systematic density-functional calculations have been performed to address an important issue for CO oxidation on redox ceria: the role of lattice oxygen. One major findings is that CO easily grasps one lattice oxygen atom to form CO2 − and CO2 on CeO2 (111) and Ce0.75Zr0.25O2 (111) with small activation energies. Zr dopants facilitate the reduction of Ce+4 to Ce+3 and hence weaken the Ce–O bonds, which benefit the direct formation and release of CO2. Zr dopants facilitate the reduction of Ce(IV) to Ce(III) and hence weaken the Ce–O bonds, which benefit the direct oxidation of CO on Zr-doped ceria.