title: Ultrathin LiCoO2Nanosheets: An Efficient Water-Oxidation Catalyst.
abstract: Ultrathin cation-exchanged layered metal oxides are promising for many applications, while such substances are barely successfully synthesized to show several atomic layer thickness, owing to the strong electrostatic force between the adjacent layers. Herein, we took LiCoO2, a prototype cation-exchanged layered metal oxide, as an example to study. By developing a simple synthetic route, we synthesized LiCoO2nanosheets with 5-6 cobalt oxide layers, which are the thinnest ever reported. Ultrathin nanosheets thus prepared showed a surprising coexistence of increased oxidation state of cobalt ions and oxygen vacancy, as demonstrated by magnetic susceptibility, X-ray photoelectron, electron paramagnetic resonance, and X-ray absorption fine spectra. This unique feature enables a higher electronic conduction and electrophilicity to the adsorbed oxygen than the bulk. Consequently ultrathin LiCoO2nanosheets provided a current density of 10 mA cm-2at a small overpotential of a mere 0.41 V and a small Tafel slope of ∼88 mV/decade, which is strikingly followed by an excellent cycle life. The findings reported in this work suggest that ultrathin cation-exchanged layered metal oxides could be a next generation of advanced catalysts for oxygen evolution reaction.
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.
authors.forename: Jianghao
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, P. R. China.
authors.forename: Liping
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.
authors.forename: Haiquan
authors.initials: H
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, P. R. China.
authors.forename: Yuelan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.
authors.forename: Xiangli
authors.initials: X
authors.lastname: Che
authors.affiliation: Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, P. R. China.|State Key Laboratory of Inorganic Synthesis & Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, P. R. China.
authors.forename: Guangshe
authors.identifier: http://orcid.org/0000-0002-3278-1804
authors.initials: G
authors.lastname: Li
keywords: LiCoO2; electrocatalysis; mixed state; nanosheets; oxygen evolution reaction