title: Surface structure dependent electrocatalytic activity of Co₃O₄ anchored on graphene sheets toward oxygen reduction reaction.
abstract: Catalytic activity is primarily a surface phenomenon, however, little is known about Co₃O₄ nanocrystals in terms of the relationship between the oxygen reduction reaction (ORR) catalytic activity and surface structure, especially when dispersed on a highly conducting support to improve the electrical conductivity and so to enhance the catalytic activity. Herein, we report a controllable synthesis of Co₃O₄ nanorods (NR), nanocubes (NC) and nano-octahedrons (OC) with the different exposed nanocrystalline surfaces ({110}, {100}, and {111}), uniformly anchored on graphene sheets, which has allowed us to investigate the effects of the surface structure on the ORR activity. Results show that the catalytically active sites for ORR should be the surface Co²⁺ ions, whereas the surface Co³⁺ ions catalyze CO oxidation, and the catalytic ability is closely related to the density of the catalytically active sites. These results underscore the importance of morphological control in the design of highly efficient ORR catalysts.
authors.affiliation: Department of Chemistry, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China. chjwxiao@hust.edu.cn
authors.forename: Junwu
authors.initials: J
authors.lastname: Xiao
authors.forename: Qin
authors.initials: Q
authors.lastname: Kuang
authors.forename: Shihe
authors.initials: S
authors.lastname: Yang
authors.forename: Fei
authors.initials: F
authors.lastname: Xiao
authors.forename: Shuai
authors.initials: S
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Guo
mesh_terms: D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*
chemical_list: D010087:Oxides; D003035:Cobalt; D006108:Graphite; D010100:Oxygen; C060728:cobalt oxide
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