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Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity
Atomic dispersion of dopants and control over their defect chemistry are central goals in the development of oxide nanoparticles for functional materials with dedicated electronic, optical or magnetic properties. We produced highly dispersed oxide nanocubes with atomic distribution of cobalt ions in...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756418/ https://www.ncbi.nlm.nih.gov/pubmed/32677720 http://dx.doi.org/10.1002/chem.202002817 |
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author | Schwab, Thomas Niedermaier, Matthias Zickler, Gregor A. Ončák, Milan Diwald, Oliver |
author_facet | Schwab, Thomas Niedermaier, Matthias Zickler, Gregor A. Ončák, Milan Diwald, Oliver |
author_sort | Schwab, Thomas |
collection | PubMed |
description | Atomic dispersion of dopants and control over their defect chemistry are central goals in the development of oxide nanoparticles for functional materials with dedicated electronic, optical or magnetic properties. We produced highly dispersed oxide nanocubes with atomic distribution of cobalt ions in substitutional sites of the MgO host lattice via metal organic chemical vapor synthesis. Vacuum annealing of the nanoparticle powders up to 1173 K has no effect on the shape of the individual particles and only leads to moderate particle coarsening. Such materials processing, however, gives rise to the electronic reduction of particle surfaces, which—upon O(2) admission—stabilize anionic oxygen radicals that are accessible to UV/Vis diffuse reflectance and electron paramagnetic resonance (EPR) spectroscopy. Multi‐reference quantum chemical calculations show that the optical bands observed mainly originate from transitions into (4)A(2g) ((4)F), (4)T(1g) ((4)P) states with a contribution of transitions into (2)T(1g), (2)T(2g) ((2)G) states through spin‐orbit coupling and gain intensity through vibrational motion of the MgO lattice or the asymmetric ion field. Related nanostructures are a promising material system for single atomic site catalysis. At the same time, it represents an extremely valuable model system for the study of interfacial electron transfer processes that are key to nanoparticle chemistry and photochemistry at room temperature, and in heterogeneous catalysis. |
format | Online Article Text |
id | pubmed-7756418 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-77564182020-12-28 Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity Schwab, Thomas Niedermaier, Matthias Zickler, Gregor A. Ončák, Milan Diwald, Oliver Chemistry Full Papers Atomic dispersion of dopants and control over their defect chemistry are central goals in the development of oxide nanoparticles for functional materials with dedicated electronic, optical or magnetic properties. We produced highly dispersed oxide nanocubes with atomic distribution of cobalt ions in substitutional sites of the MgO host lattice via metal organic chemical vapor synthesis. Vacuum annealing of the nanoparticle powders up to 1173 K has no effect on the shape of the individual particles and only leads to moderate particle coarsening. Such materials processing, however, gives rise to the electronic reduction of particle surfaces, which—upon O(2) admission—stabilize anionic oxygen radicals that are accessible to UV/Vis diffuse reflectance and electron paramagnetic resonance (EPR) spectroscopy. Multi‐reference quantum chemical calculations show that the optical bands observed mainly originate from transitions into (4)A(2g) ((4)F), (4)T(1g) ((4)P) states with a contribution of transitions into (2)T(1g), (2)T(2g) ((2)G) states through spin‐orbit coupling and gain intensity through vibrational motion of the MgO lattice or the asymmetric ion field. Related nanostructures are a promising material system for single atomic site catalysis. At the same time, it represents an extremely valuable model system for the study of interfacial electron transfer processes that are key to nanoparticle chemistry and photochemistry at room temperature, and in heterogeneous catalysis. John Wiley and Sons Inc. 2020-10-19 2020-12-04 /pmc/articles/PMC7756418/ /pubmed/32677720 http://dx.doi.org/10.1002/chem.202002817 Text en 2020 The Authors published by Wiley-VCH GmbH This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Full Papers Schwab, Thomas Niedermaier, Matthias Zickler, Gregor A. Ončák, Milan Diwald, Oliver Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity |
title | Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity |
title_full | Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity |
title_fullStr | Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity |
title_full_unstemmed | Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity |
title_short | Isolated Cobalt Ions Embedded in Magnesium Oxide Nanostructures: Spectroscopic Properties and Redox Activity |
title_sort | isolated cobalt ions embedded in magnesium oxide nanostructures: spectroscopic properties and redox activity |
topic | Full Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756418/ https://www.ncbi.nlm.nih.gov/pubmed/32677720 http://dx.doi.org/10.1002/chem.202002817 |
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