A DFT Study of CO Catalytic Oxidation by N₂O or O₂ on the Co₃O₄(110) Surface

The reaction mechanisms for CO catalytic oxidation by N 2 O or O 2 on the Co 3 O 4 (110) surface were studied by DFT slab calculations. CO chemisorbs preferably at a surface Co 3+ site. After the Co 3+ site is completely covered, CO adsorbs at the neighboring twofold coordinated surface oxygen atom bonded to Co 2+ and Co 3+ cations, resulting in the formation of CO 2 and an oxygen vacancy with a low energy barrier of 0.033 eV, which rationalizes the experimental observation that Co 3 O 4 ‐based systems are active for CO oxidation at low temperatures. N 2 O or O 2 interacts with the oxygen vacancy site to regenerate the surface, leaving N 2 or the activated O 2 − species to be attacked by the second CO to yield CO 2 to proceed with the catalytic cycle. The CO oxidation reaction follows the Mars– van Krevelen mechanism.