title: Co₃O₄ nanocrystals on graphene as a synergistic catalyst for oxygen reduction reaction.
abstract: Catalysts for oxygen reduction and evolution reactions are at the heart of key renewable-energy technologies including fuel cells and water splitting. Despite tremendous efforts, developing oxygen electrode catalysts with high activity at low cost remains a great challenge. Here, we report a hybrid material consisting of Co₃O₄ nanocrystals grown on reduced graphene oxide as a high-performance bi-functional catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Although Co₃O₄ or graphene oxide alone has little catalytic activity, their hybrid exhibits an unexpected, surprisingly high ORR activity that is further enhanced by nitrogen doping of graphene. The Co₃O₄/N-doped graphene hybrid exhibits similar catalytic activity but superior stability to Pt in alkaline solutions. The same hybrid is also highly active for OER, making it a high-performance non-precious metal-based bi-catalyst for both ORR and OER. The unusual catalytic activity arises from synergetic chemical coupling effects between Co₃O₄ and graphene.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305, USA.
authors.forename: Yongye
authors.initials: Y
authors.lastname: Liang
authors.forename: Yanguang
authors.initials: Y
authors.lastname: Li
authors.forename: Hailiang
authors.initials: H
authors.lastname: Wang
authors.forename: Jigang
authors.initials: J
authors.lastname: Zhou
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Tom
authors.initials: T
authors.lastname: Regier
authors.forename: Hongjie
authors.initials: H
authors.lastname: Dai
mesh_terms: D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D003246:Conservation of Energy Resources; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D059205:Renewable Energy
chemical_list: D010087:Oxides; D003035:Cobalt; D006108:Graphite; D009584:Nitrogen; C060728:cobalt oxide