Holey 2D Nanosheets of Low-Valent Manganese Oxides with an Excellent Oxygen Catalytic Activity and a High Functionality as a Catalyst for Li–O2 Batteries

Kanyaporn Adpakpang, Seung Mi Oh, Daniel Adjei Agyeman, Xiaoyan Jin, Nutpaphat Jarulertwathana, In Young Kim, Thapanee Sarakonsri, Yong Mook Kang, Seong Ju Hwang

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Holey 2D nanosheets of low-valent Mn2O3 can be synthesized by thermally induced phase transition of exfoliated layered MnO2 nanosheets. The heat treatment of layered MnO2 nanosheets at elevated temperatures leads not only to transitions to low-valent manganese oxides but also to the creation of surface hole in the 2D nanosheet crystallites. Despite distinct phase transitions, highly anisotropic 2D morphology of the precursor MnO2 material remains intact upon the heat treatment whereas the diameter of surface hole becomes larger with increasing heating temperature. The obtained holey 2D Mn2O3 nanosheets show promising electrocatalyst performances for oxygen evolution reaction, which are much superior to that of nonporous Mn2O3 crystal. Among the present materials, the holey Mn2O3 nanosheet calcined at 500 °C displays the best electrocatalyst functionality with markedly decreased overpotential, indicating the importance of heating condition in optimizing the electrocatalytic activity. Of prime importance is that this material shows much better catalytic activity for Li–O2 batteries than does nonporous Mn2O3, underscoring the critical role of porous 2D morphology in this functionality. This study clearly demonstrates the unique advantage of holey 2D nanosheet morphology in exploring economically feasible transition metal oxide-based electrocatalysts and electrodes for Li–O2 batteries.

Original languageEnglish
Article number1707106
JournalAdvanced Functional Materials
Issue number17
StatePublished - 25 Apr 2018

Bibliographical note

Funding Information:
K.A., S.M.O., and D.A.A. contributed equally to this work. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. NRF-2017R1A2A1A17069463) and by the Korea government (MSIT) (No. NRF-2017R1A5A1015365). K.A. acknowledges postdoctoral fellowship from Vidyasirimedhi Institute of Science and Technology. Y.-M. Kang acknowledges National Research Foundation of Korea (NRF) grant, funded by the Korea government (MSIT) (NRF-2017R1A2B3004383). The experiments at PAL were supported in part by MOST and POSTECH.

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • Li–O batteries
  • electrocatalysts
  • holey metal oxide nanosheets
  • oxygen evolution reaction
  • phase transition


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