Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide
Mn-Co containing spinel oxides are promising, low-cost electrocatalysts for the oxygen reduction reaction (ORR). Most studies are devoted to the design of porous Mn-Co spinels or to strongly coupled hybrids (e.g., MnCo2 O4 /N-doped-rmGO) to maximize the mass efficiency. The lack of analyses by metal...
Saved in:
Main Authors: | , , , , , , |
---|---|
Other Authors: | |
Format: | Article |
Language: | English |
Published: |
2020
|
Subjects: | |
Online Access: | https://hdl.handle.net/10356/138950 |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Institution: | Nanyang Technological University |
Language: | English |
id |
sg-ntu-dr.10356-138950 |
---|---|
record_format |
dspace |
spelling |
sg-ntu-dr.10356-1389502021-01-20T02:46:12Z Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide Zhou, Ye Sun, Shengnan Xi, Shibo Duan, Yan Sritharan, Thirumany Du, Yonghua Xu, Zhichuan Jason School of Materials Science and Engineering Solar Fuel Laboratory Energy Research Institute @ NTU (ERI@N) Engineering::Materials Antibonding Orbitals Edge-sharing Octahedra Mn-Co containing spinel oxides are promising, low-cost electrocatalysts for the oxygen reduction reaction (ORR). Most studies are devoted to the design of porous Mn-Co spinels or to strongly coupled hybrids (e.g., MnCo2 O4 /N-doped-rmGO) to maximize the mass efficiency. The lack of analyses by metal oxide intrinsic activity (activity normalized to catalysts' surface area) hinders the development of fundamental understanding of the physicochemical principles behind the catalytic activities. A systematic study on the composition dependence of ORR in ZnCox Mn2-x O4 (x = 0.0-2.0) spinel is presented here with special attention to the role of edge sharing [Cox Mn1-x O6 ] octahedra in the spinel structure. The ORR specific activity of ZnCox Mn2-x O4 spans across a potential window of 200 mV, indicating an activity difference of ≈3 orders of magnitude. The curve of composition-dependent ORR specific activity as a function of Co substitution exhibits a volcano shape with an optimum Mn/Co ratio of 0.43. It is revealed that the modulated eg occupancy of active Mn cations (0.3-0.9), as a consequence of the superexchange effect between edge sharing [CoO6 ] and [MnO6 ], reflects the ORR activity of edge sharing [Cox Mn1-x O6 ] octahedra in the ZnCox Mn2-x O4 spinel oxide. These findings offer crucial insights in designing spinel oxide catalysts with fine-tuned eg occupancy for efficient catalysis. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) 2020-05-14T04:59:07Z 2020-05-14T04:59:07Z 2018 Journal Article Zhou, Y., Sun, S., Xi, S., Duan, Y., Sritharan, T., Du, Y., & Xu, Z. J. (2018). Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide. Advanced Materials, 30(11), 1705407-. doi:10.1002/adma.201705407 0935-9648 https://hdl.handle.net/10356/138950 10.1002/adma.201705407 29356120 2-s2.0-85040769491 11 30 en Advanced Materials © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. All rights reserved. This paper was published in Advanced Materials and is made available with permission of WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
institution |
Nanyang Technological University |
building |
NTU Library |
continent |
Asia |
country |
Singapore Singapore |
content_provider |
NTU Library |
collection |
DR-NTU |
language |
English |
topic |
Engineering::Materials Antibonding Orbitals Edge-sharing Octahedra |
spellingShingle |
Engineering::Materials Antibonding Orbitals Edge-sharing Octahedra Zhou, Ye Sun, Shengnan Xi, Shibo Duan, Yan Sritharan, Thirumany Du, Yonghua Xu, Zhichuan Jason Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide |
description |
Mn-Co containing spinel oxides are promising, low-cost electrocatalysts for the oxygen reduction reaction (ORR). Most studies are devoted to the design of porous Mn-Co spinels or to strongly coupled hybrids (e.g., MnCo2 O4 /N-doped-rmGO) to maximize the mass efficiency. The lack of analyses by metal oxide intrinsic activity (activity normalized to catalysts' surface area) hinders the development of fundamental understanding of the physicochemical principles behind the catalytic activities. A systematic study on the composition dependence of ORR in ZnCox Mn2-x O4 (x = 0.0-2.0) spinel is presented here with special attention to the role of edge sharing [Cox Mn1-x O6 ] octahedra in the spinel structure. The ORR specific activity of ZnCox Mn2-x O4 spans across a potential window of 200 mV, indicating an activity difference of ≈3 orders of magnitude. The curve of composition-dependent ORR specific activity as a function of Co substitution exhibits a volcano shape with an optimum Mn/Co ratio of 0.43. It is revealed that the modulated eg occupancy of active Mn cations (0.3-0.9), as a consequence of the superexchange effect between edge sharing [CoO6 ] and [MnO6 ], reflects the ORR activity of edge sharing [Cox Mn1-x O6 ] octahedra in the ZnCox Mn2-x O4 spinel oxide. These findings offer crucial insights in designing spinel oxide catalysts with fine-tuned eg occupancy for efficient catalysis. |
author2 |
School of Materials Science and Engineering |
author_facet |
School of Materials Science and Engineering Zhou, Ye Sun, Shengnan Xi, Shibo Duan, Yan Sritharan, Thirumany Du, Yonghua Xu, Zhichuan Jason |
format |
Article |
author |
Zhou, Ye Sun, Shengnan Xi, Shibo Duan, Yan Sritharan, Thirumany Du, Yonghua Xu, Zhichuan Jason |
author_sort |
Zhou, Ye |
title |
Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide |
title_short |
Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide |
title_full |
Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide |
title_fullStr |
Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide |
title_full_unstemmed |
Superexchange effects on oxygen reduction activity of edge-sharing [CoxMn1-xO6] octahedra in spinel oxide |
title_sort |
superexchange effects on oxygen reduction activity of edge-sharing [coxmn1-xo6] octahedra in spinel oxide |
publishDate |
2020 |
url |
https://hdl.handle.net/10356/138950 |
_version_ |
1690658365433184256 |