Facet-Dependent Oxygen Reduction Reaction Activity on the Surfaces of Co3O4

The mechanisms for oxygen reduction reaction (ORR) on the naturally exposed (110) and (111) surfaces of Co3O4 have been investigated with density functional theory (DFT) calculations. Depending on the vertical cutting place, there are type A and B surfaces for each of the (110) and (111) surfaces of Co3O4. Our DFT calculations reveal that the Co3O4 (110) type B and (111) type B surfaces have ORR catalytic activities. In addition, the ORR activity on the (110) type B surface is better than the (111) type B surface. The rate-determining step on both surfaces is thermodynamically depending on the *OH desorption process. If the solvation effects are taken into accounts, the chemically adsorbed water molecules enhance the ORR activity. According to the barrier heights calculations, O-2 -> *O-2 -> *OOH -> *O + H2O -> *OH -> H2O route is the most favorable ORR pathway.

Automated summary

The mechanisms and activities of oxygen reduction reaction (ORR) on the (110) and (111) surfaces of Co3O4 were investigated using density functional theory (DFT) calculations. It was found that the (110) type B surface exhibited better ORR activity, with the rate-determining step depending on *OH desorption. Considering solvent effects, chemically adsorbed water molecules enhanced the ORR activity. The most favorable ORR pathway was determined to be O-2 -> *O-2 -> *OOH -> *O + H2O -> *OH -> H2O.