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Jahn–Teller Disproportionation Induced Exfoliation of Unit‐Cell Scale ϵ‐MnO 2
Author(s) -
Jiang Yilan,
Yuan Long,
Wang Xiyang,
Zhang Wei,
Liu Jinghai,
Wu Xiaofeng,
Huang Keke,
Li Yefei,
Liu Zhipan,
Feng Shouhua
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202010246
Subject(s) - disproportionation , exfoliation joint , van der waals force , materials science , nanosheet , manganese , metastability , crystallography , nickel , chemical physics , nanotechnology , chemistry , catalysis , molecule , metallurgy , biochemistry , graphene , organic chemistry
Exfoliation of non‐layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top‐down method to exfoliate ϵ‐MnO 2 nanosheets in a family of charge‐ordered La 1− x AE x MnO 3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn–Teller disproportionation effect of Mn 3+ and bond‐strength differences. ϵ‐MnO 2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton‐induced Mn 3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two‐dimensional nanosheet materials with non‐layered structures.