Methane Dissociation on the Ceria (111) Surface

The complete oxidation of methane into water and carbon dioxide on the (111) surface of ceria is considered within a DFT + U framework in order to gain insight into the coke-free operation of solid oxide fuel cells with ceria-containing anodes. Preferred adsorption sites and energies are determined for CH x ( x = 0, ..., 3), H, and CO, together with transition states and kinetic barriers along the complete pathway from CH 4 to H 2 O and CO 2 . The results presented are in excellent agreement with existing theoretical and experimental work suggesting that ceria is more easily reduced by CO than by H 2 and offer an explanation for the apparently inconsistent observations of carbon coke formation in Ni−ceria anodes and the stable, coke-free oxidation of methane in Cu−ceria anodes.