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Oxygen vacancy formation and reduction properties of β-MnO2 grain boundaries and the potential for high electrochemical performance

Lookup NU author(s): Dr James DawsonORCiD

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Abstract

© 2014 American Chemical Society.In recent years, the nanostructuring of rutile (β-)MnO2 has been shown to vastly improve its properties and performance in a number of technological applications. The contrast between the strong electrochemical properties of the nanostructured material and the bulk material that shows limited Li intercalation and electrochemical capacitance is not yet fully understood. In this work, we investigate the structure, stability and catalytic properties of four tilt grain boundaries in β-MnO2 using interatomic potential methods. By considering the γ-surfaces of each of the grain boundaries, we are able to find the lowest energy configurations for each grain boundary structure. For each grain boundary, we observe a significant decrease in the oxygen vacancy energies in and around the grain boundaries compared to bulk β-MnO2 and also the bulk-like structures in the grain boundary cells. The reduction of Mn4+ to Mn3+ is also considered and again is shown to be preferable at the boundaries. These energies suggest a potentially higher catalytic activity at the grain boundaries of β-MnO2. The results are also placed into context with recent calculations of β-MnO2 surfaces to produce a more detailed understanding into this important phenomenon.


Publication metadata

Author(s): Dawson JA, Tanaka I

Publication type: Article

Publication status: Published

Journal: ACS Applied Materials and Interfaces

Year: 2014

Volume: 6

Issue: 20

Pages: 17776-17784

Print publication date: 22/10/2014

Online publication date: 06/10/2014

Acceptance date: 23/09/2014

ISSN (print): 1944-8244

ISSN (electronic): 1944-8252

Publisher: American Chemical Society

URL: https://doi.org/10.1021/am504351p

DOI: 10.1021/am504351p


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