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. (20th February 2018)

• Record Type: Journal Article
• Authors: Adpakpang, Kanyaporn; Oh, Seung Mi; Agyeman, Daniel Adjei; Jin, Xiaoyan; Jarulertwathana, Nutpaphat; Kim, In Young; Sarakonsri, Thapanee; Kang, Yong‐Mook; Hwang, Seong‐Ju
• Is Part Of: Advanced functional materials. Volume 28:Number 17(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-02-20
• Subjects: electrocatalysts -- holey metal oxide nanosheets -- Li–O2 batteries -- oxygen evolution reaction -- phase transition; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201707106
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Holey 2D nanosheets of low‐valent Mn2 O3 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 Mn2 O3 nanosheets show promising electrocatalyst performances for oxygen evolution reaction, which are much superior to that of nonporous Mn2 O3 crystal. Among the present materials, the holey Mn2 O3 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 Mn2 O3, 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. Abstract : An effective synthetic route to novel holey 2D nanosheets of low‐valent manganese oxides is developed by finely controlled heat treatment of exfoliated MnO2 nanosheet. The resulting holey 2D Mn2 O3 nanosheets show promising functionalities as oxygen electrocatalysts and cathode catalysts for Li–O2 batteries with excellent cyclability, underscoring the remarkable advantage of holey 2D nanosheet morphology.