Nonstoichiometric Oxygen in Mn–Ga–O Spinels: Reduction Features of the Oxides and Their Catalytic Activity Full article
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RSC Advances
ISSN: 2046-2069 |
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| Output data | Year: 2018, Volume: 8, Number: 21, Pages: 11598-11607 Pages count : 10 DOI: 10.1039/c7ra11557a | ||||||
| Tags | THIN-FILMS; MANGANESE OXIDES; CO OXIDATION; NANOPARTICLES; TEMPERATURE; PERFORMANCE; COMBUSTION; MN2O3 | ||||||
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Funding (1)
| 1 | Federal Agency for Scientific Organizations | 0303-2016-0002 |
Abstract:
The subject of this study was the content of oxygen in mixed oxides with the spinel structure Mn1.7Ga1.3O4 that were synthesized by coprecipitation and thermal treatment in argon at 600–1200 °C. The study revealed the presence of excess oxygen in “low-temperature” oxides synthesized at 600–800 °C. The occurrence of superstoichiometric oxygen in the structure of Mn1.7Ga1.3O4+δ oxide indicates the formation of cationic vacancies, which shows up as a decreased lattice parameter in comparison with “high-temperature” oxides synthesized at 1000–1200 °C; the additional negative charge is compensated by an increased content of Mn3+ cations according to XPS. The low-temperature oxides containing excess oxygen show a higher catalytic activity in CO oxidation as compared to the high-temperature oxides, the reaction temperature was 275 °C. For oxides prepared at 600 and 800 °C, catalytic activity was 0.0278 and 0.0048 cm3 (CO) per g per s, and further increase in synthesis temperature leads to a drop in activity to zero. The process of oxygen loss by Mn1.7Ga1.3O4+δ was studied in detail by TPR, in situ XRD and XPS. It was found that the hydrogen reduction of Mn1.7Ga1.3O4+δ proceeds in two steps. In the first step, excess oxygen is removed, Mn1.7Ga1.3O4+δ → Mn1.7Ga1.3O4. In the second step, Mn3+ cations are reduced to Mn2+ in the spinel structure with a release of manganese oxide as a single crystal phase, Mn1.7Ga1.3O4 → Mn2Ga1O4 + MnO.
Cite:
Bulavchenko O.A.
, Venediktova O.S.
, Afonasenko T.N.
, Tsyrul'nikov P.G.
, Saraev A.A.
, Kaichev V.V.
, Tsybulya S.V.
Nonstoichiometric Oxygen in Mn–Ga–O Spinels: Reduction Features of the Oxides and Their Catalytic Activity
RSC Advances. 2018.
V.8. N21. P.11598-11607. DOI: 10.1039/c7ra11557a
WOS
Scopus
РИНЦ
AN
PMID
OpenAlex
Nonstoichiometric Oxygen in Mn–Ga–O Spinels: Reduction Features of the Oxides and Their Catalytic Activity
RSC Advances. 2018.
V.8. N21. P.11598-11607. DOI: 10.1039/c7ra11557a
WOS
Scopus
РИНЦ
AN
PMID
OpenAlex
Files:
Full text from publisher
Dates:
| Submitted: | Oct 19, 2017 |
| Accepted: | Mar 9, 2018 |
| Published online: | Mar 27, 2018 |
Identifiers:
| Web of science: | WOS:000428672500041 |
| Scopus: | 2-s2.0-85044627083 |
| Elibrary: | 35488796 |
| Chemical Abstracts: | 2018:602427 |
| PMID: | 35542767 |
| OpenAlex: | W2794568465 |