Reducibility of Al3+-Modified Co3O4: Influence of Aluminum Distribution Full article
| Journal |
Materials
ISSN: 1996-1944 |
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| Output data | Year: 2023, Volume: 16, Number: 18, Article number : 6216, Pages count : 15 DOI: 10.3390/ma16186216 | ||||
| Tags | reducibility; cobalt oxide; in situ XRD; solid solution; catalyst; modification | ||||
| Authors |
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| Affiliations |
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Funding (1)
| 1 | Ministry of Science and Higher Education of the Russian Federation | 075-15-2022-263 |
Abstract:
The reduction of Co-based oxides doped with Al3+ ions has been studied using in situ XRD and TPR techniques. Al3+-modified Co3O4 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 Al3+ cations were dissolved in the Co3O4 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)3O4 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)3O4 → (Co,Al)O → Co. Depending on the Al distribution, the course of reduction changes. In the case of the inhomogeneous (Co,Al)3O4 solid solution, Al stabilizes intermediate Co(II)-Al(III) oxides during reduction. When Al3+ ions are predominantly on the surface of the Co3O4 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 Co3O4/γ-Al2O3-supported catalysts. These changes in the reduction properties can significantly affect the state of an active component of the Co-based catalysts.
Cite:
Cherepanova S.V.
, Koemets E.G.
, Gerasimov E.Y.
, Simentsova I.I.
, Bulavchenko O.A.
Reducibility of Al3+-Modified Co3O4: Influence of Aluminum Distribution
Materials. 2023. V.16. N18. 6216 :1-15. DOI: 10.3390/ma16186216 WOS Scopus РИНЦ AN OpenAlex
Reducibility of Al3+-Modified Co3O4: Influence of Aluminum Distribution
Materials. 2023. V.16. N18. 6216 :1-15. DOI: 10.3390/ma16186216 WOS Scopus РИНЦ AN OpenAlex
Dates:
| Submitted: | Jul 31, 2023 |
| Accepted: | Aug 26, 2023 |
| Published print: | Sep 14, 2023 |
| Published online: | Sep 14, 2023 |
Identifiers:
| Web of science: | WOS:001073611200001 |
| Scopus: | 2-s2.0-85172862135 |
| Elibrary: | 55293356 |
| Chemical Abstracts: | 2023:2021197 |
| OpenAlex: | W4386780780 |