Abstract
Layered δ-MnO2 (birnessites) are ubiquitous in nature and have also been reported to work as promising water oxidation catalysts or rechargeable alkali-ion battery cathodes when fabricated under appropriate conditions. Although tremendous effort has been spent on resolving the structure of natural/synthetic layered δ-MnO2 in the last few decades, no conclusive result has been reached. In this Article, we report an environmentally friendly route to synthesizing homogeneous Cu-rich layered δ-MnO2 nanoflowers in large scale. The local and average structure of synthetic Cu-rich layered δ-MnO2 has been successfully resolved from combined Mn/Cu K-edge extended X-ray fine structure spectroscopy and X-ray and neutron total scattering analysis. It is found that appreciable amounts (∼8%) of Mn vacancies are present in the MnO2 layer and Cu2+ occupies the interlayer sites above/below the vacant Mn sites. Effective hydrogen bonding among the interlayer water molecules and adjacent layer O ions has also been observed for the first time. These hydrogen bonds are found to play the key role in maintaining the intermediate and long-range stacking coherence of MnO2 layers. Quantitative analysis of the turbostratic stacking disorder in this compound was achieved using a supercell approach coupled with anisotropic particle-size-effect modeling. The present method is expected to be generally applicable to the structural study of other technologically important nanomaterials.
Original language | English |
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Pages (from-to) | 6873-6882 |
Number of pages | 10 |
Journal | Inorganic Chemistry |
Volume | 57 |
Issue number | 12 |
DOIs | |
State | Published - Jun 18 2018 |
Bibliographical note
Publisher Copyright:Copyright © 2018 American Chemical Society.
Funding
This work was principally supported through the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Early Career Research Program Award KC040602, under Contract DE-AC05-00OR22725. Research conducted at the NOMAD beamline at ORNL’s SNS was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, U.S. DOE. Research at the 11-ID-B beamline used resources of the APS, a U.S. DOE, Office of Science User Facility, operated for the U.S. DOE, Office of Science, by ANL under Contract DE-AC02-06CH11357. E.H. and X.-Q.Y. at BNL were supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. DOE through the Advanced Battery Materials Research Program, including battery 500, under Contract DE-SC0012704. This research used resources 8-ID of the National Synchrotron Light Source II, a U.S. DOE, Office of Science User Facility, operated for the U.S. DOE, Office of Science, by BNL under Contract DE-SC0012704. Materials synthesis and TEM work was conducted at the Center for Nanophase Materials Sciences, which is a U.S. DOE, Office of Science User Facility. Partial salary support was provided by the National Science Foundation under Grant OIA 1355438 (to L.Y.) and Grant DMR 1455154 (to B.S.G.). We thank Dr. Yan Chen and Dr. Kai Wang for their assistance in collecting DSC and SEM data.
Funders | Funder number |
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Office of Basic Energy Sciences | DE-AC05-00OR22725, KC040602 |
Office of Basic Energy Sciences | |
Scientific User Facilities Division | |
Michigan State University-U.S. Department of Energy (MSU-DOE) Plant Research Laboratory | |
National Science Foundation (NSF) | OIA 1355438, DMR 1455154 |
Michigan State University-U.S. Department of Energy (MSU-DOE) Plant Research Laboratory | |
Office of Science Programs | |
Office of Energy Efficiency and Renewable Energy | |
Argonne National Laboratory | DE-AC02-06CH11357 |
Brookhaven National Laboratory (BNL) | |
American Society for Pain Management Nursing | |
Vehicle Technologies Office of the U.S. Department of Energy Battery Materials Research | DE-SC0012704 |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry