title: Homogeneous cationic substitution for two-dimensional layered metal oxide nanosheets via a galvanic exchange reaction.
abstract: The galvanic exchange reaction of an exfoliated 2D layered metal oxide nanosheet (NS) with excess substituent metal cations enables the synthesis of a mixed metal oxide 2D NS with controllable cation compositions and physicochemical properties. The reaction of the exfoliated MnO2NS with Fe2+or Sn2+ions at 90 °C induces the uniform galvanic replacement of Mn ions with these substituent ions, whereas the same reaction at 25 °C results in the intercalative restacking of the negatively-charged MnO2NS with Fe2+or Sn2+cations. Upon the galvanic exchange reaction, the highly anisotropic MnO22D NS retains its original 2D morphology and layered structure, which is in stark contrast to 0D nanoparticles yielding hollow nanospheres via the galvanic exchange reaction. This observation is attributable to the thin thickness of the 2D NS allowing the simultaneous replacement of all the component surface-exposed metal ions. The resulting substitution of the MnO2NS with Fe and Sn ions remarkably improves the electrode performance of the carbon-coated derivatives of the MnO2NS for lithium ion batteries. The present study clearly demonstrates that the galvanic exchange reaction can provide an efficient method not only to tailor cation compositions but also to improve the functionalities of 2D metal oxide NSs and their carbon-coated derivatives.
authors.affiliation: Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea. hwangsju@ewha.ac.kr.
authors.forename: Joohyun
authors.identifier: http://orcid.org/0000-0003-3880-2634
authors.initials: J
authors.lastname: Lim
authors.affiliation: Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea. hwangsju@ewha.ac.kr.
authors.forename: Jang Mee
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea. hwangsju@ewha.ac.kr.
authors.forename: Boyeon
authors.initials: B
authors.lastname: Park
authors.affiliation: Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea. hwangsju@ewha.ac.kr.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Jin
authors.affiliation: Department of Chemistry and Nanoscience, College of Natural Sciences, Ewha Womans University, Seoul 03760, Korea. hwangsju@ewha.ac.kr.
authors.forename: Seong-Ju
authors.initials: SJ
authors.lastname: Hwang