title: Tuning the Electronic Bandgap: An Efficient Way To Improve the Electrocatalytic Activity of Carbon-Supported Co3O4Nanocrystals for Oxygen Reduction Reactions.
abstract: The achievement of crystal-lattice tuning along low Miller index planes to decrease the bandgap of spinel transition-metal oxides may be an effective way to enhance their electrocatalytic activity for the oxygen reduction reaction (ORR). Herein, we have prepared spherical Co3O4nanoparticles with a preferred orientation along the (111) plane by direct nucleation and growth of the oxide on graphitized carbon black (GCB). The formation of the preferred (111) oxide is attributed to a unique chemical interaction at the interface between Co3O4and carbon, which results in covalent C-O-Co bonds in the hybrid. Electrocatalysis experiments in an alkaline environment revealed that the electrocatalytic activity for ORR on the preferred (111) oxide increased as a function of the degree of crystal-lattice orientation, which implies a closely intrinsic correlation between the predominant (111) plane and the catalytic activity. Because Co2+cations are enriched in this plane, they possess a narrow bandgap and unfilled conduction bands at low energy with respect to Co3+ions in the preferred (111) Co3O4, which can contribute to the absorption and activation of active oxygen and lead to improved ORR activity.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and, Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, P.R. China.
authors.forename: Hongcan
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and, Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, P.R. China.
authors.forename: Wujie
authors.initials: W
authors.lastname: Long
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and, Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, P.R. China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Song
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and, Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, P.R. China.
authors.forename: Jingjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and, Technology for Materials, Beijing University of Chemical Technology, Beijing, 100029, P.R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
keywords: bandgap; cobalt; nanoparticles; oxygen reduction reaction; supported catalysts