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Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution
The reduction of Co-based oxides doped with Al(3+) ions has been studied using in situ XRD and TPR techniques. Al(3+)-modified Co(3)O(4) oxides with the Al mole fraction Al/(Co + Al) = 1/6; 1/7.5 were prepared via coprecipitation, with further calcination at 500 and 850 °C. Using XRD and HAADF-STEM...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532862/ https://www.ncbi.nlm.nih.gov/pubmed/37763493 http://dx.doi.org/10.3390/ma16186216 |
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author | Cherepanova, Svetlana V. Koemets, Egor G. Gerasimov, Evgeny Yu. Simentsova, Irina I. Bulavchenko, Olga A. |
author_facet | Cherepanova, Svetlana V. Koemets, Egor G. Gerasimov, Evgeny Yu. Simentsova, Irina I. Bulavchenko, Olga A. |
author_sort | Cherepanova, Svetlana V. |
collection | PubMed |
description | The reduction of Co-based oxides doped with Al(3+) ions has been studied using in situ XRD and TPR techniques. Al(3+)-modified Co(3)O(4) oxides with the Al mole fraction Al/(Co + Al) = 1/6; 1/7.5 were prepared via coprecipitation, with further calcination at 500 and 850 °C. Using XRD and HAADF-STEM combined with EDS element mapping, the Al(3+) cations were dissolved in the Co(3)O(4) lattice; however, the cation distribution differed and depended on the calcination temperature. Heating at 500 °C led to the formation of an inhomogeneous (Co,Al)(3)O(4) solid solution; further treatment at 850 °C provoked the partial decomposition of mixed Co-Al oxides and the formation of particles with an Al-depleted interior and Al-enriched surface. It has been shown that the reduction of cobalt oxide by hydrogen occurs via the following transformations: (Co,Al)(3)O(4) → (Co,Al)O → Co. Depending on the Al distribution, the course of reduction changes. In the case of the inhomogeneous (Co,Al)(3)O(4) solid solution, Al stabilizes intermediate Co(II)-Al(III) oxides during reduction. When Al(3+) ions are predominantly on the surface of the Co(3)O(4) particles, the intermediate compound consists of Al-depleted and Al-enriched Co(II)-Al(III) oxides, which are reduced independently. Different distributions of elemental Co and Al in mixed oxides simulate different types of the interaction phase in Co(3)O(4)/γ-Al(2)O(3)-supported catalysts. These changes in the reduction properties can significantly affect the state of an active component of the Co-based catalysts. |
format | Online Article Text |
id | pubmed-10532862 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-105328622023-09-28 Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution Cherepanova, Svetlana V. Koemets, Egor G. Gerasimov, Evgeny Yu. Simentsova, Irina I. Bulavchenko, Olga A. Materials (Basel) Article The reduction of Co-based oxides doped with Al(3+) ions has been studied using in situ XRD and TPR techniques. Al(3+)-modified Co(3)O(4) oxides with the Al mole fraction Al/(Co + Al) = 1/6; 1/7.5 were prepared via coprecipitation, with further calcination at 500 and 850 °C. Using XRD and HAADF-STEM combined with EDS element mapping, the Al(3+) cations were dissolved in the Co(3)O(4) lattice; however, the cation distribution differed and depended on the calcination temperature. Heating at 500 °C led to the formation of an inhomogeneous (Co,Al)(3)O(4) solid solution; further treatment at 850 °C provoked the partial decomposition of mixed Co-Al oxides and the formation of particles with an Al-depleted interior and Al-enriched surface. It has been shown that the reduction of cobalt oxide by hydrogen occurs via the following transformations: (Co,Al)(3)O(4) → (Co,Al)O → Co. Depending on the Al distribution, the course of reduction changes. In the case of the inhomogeneous (Co,Al)(3)O(4) solid solution, Al stabilizes intermediate Co(II)-Al(III) oxides during reduction. When Al(3+) ions are predominantly on the surface of the Co(3)O(4) particles, the intermediate compound consists of Al-depleted and Al-enriched Co(II)-Al(III) oxides, which are reduced independently. Different distributions of elemental Co and Al in mixed oxides simulate different types of the interaction phase in Co(3)O(4)/γ-Al(2)O(3)-supported catalysts. These changes in the reduction properties can significantly affect the state of an active component of the Co-based catalysts. MDPI 2023-09-14 /pmc/articles/PMC10532862/ /pubmed/37763493 http://dx.doi.org/10.3390/ma16186216 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Cherepanova, Svetlana V. Koemets, Egor G. Gerasimov, Evgeny Yu. Simentsova, Irina I. Bulavchenko, Olga A. Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution |
title | Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution |
title_full | Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution |
title_fullStr | Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution |
title_full_unstemmed | Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution |
title_short | Reducibility of Al(3+)-Modified Co(3)O(4): Influence of Aluminum Distribution |
title_sort | reducibility of al(3+)-modified co(3)o(4): influence of aluminum distribution |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10532862/ https://www.ncbi.nlm.nih.gov/pubmed/37763493 http://dx.doi.org/10.3390/ma16186216 |
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