Facet-Dependent Oxygen Reduction Reaction Activity on the Surfaces of Co_(3)O_(4)

摘要

The mechanisms for oxygen reduction reaction(ORR)on the naturally exposed(110)and(111)surfaces of Co_(3)O_(4)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 Co_(3)O_(4).Our DFT calculations reveal that the Co_(3)O_(4)(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 ratedetermining 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+H_(2)O→^(*)OH→H_(2)O route is the most favorable ORR pathway.