Structure and Electronic Properties of Ca-Doped CeO2 and Implications on Catalytic Activity: An Experimental and Theoretical Study

Doping CeO 2 with for example, Ca gives an enhanced reactivity toward reduction of SO 2 by CO, and total combustion of methane. Theoretical modeling using static minimizations and molecular dynamics (MD) simulations of the doped (110) face in combination with ab initio quantum chemical cluster models shows large effects on the Ce(IV)/Ce(III) balance due to the doping. Computed oxygen-to-cerium charge-transfer energies are strongly reduced as a result of the introduction of defects and oxygen vacancies, but not sufficiently to explain the observed reactivities. The structures resulting from the MD simulations for both the doped and undoped material are in good agreement with recent experimental pulsed neutron scattering results.