Comparative Study of Electrical Conduction and Oxygen Diffusion in the Rhombohedral and Bixbyite Ln6MoO12 (Ln = Er, Tm, Yb) Polymorphs
Научная публикация
| Общее |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Оригинальная
|
| Журнал |
Inorganic Chemistry
ISSN: 0020-1669
, E-ISSN: 1520-510X
|
| Вых. Данные |
Год: 2019,
Том: 58,
Номер: 7,
Страницы: 4275-4288
Страниц
: 14
DOI:
10.1021/acs.inorgchem.8b03397
|
| Авторы |
Shlyakhtina Anna V.
1
,
Lyskov Nikolay V.
2
,
Avdeev Maxim
3
,
Goffman Vladimir G.
4
,
Gorshkov Nikolay V.
4
,
Knotko Alexander V.
5
,
Kolbanev Igor V.
1
,
Karyagina Olga K.
6
,
Maslakov Konstantin I.
5
,
Shcherbakova Lidia G.
1
,
Sadovskaya Ekaterina M.
7,8
,
Sadykov Vladislav A.
7,8
,
Eremeev Nikita F.
7
|
| Организации |
| 1 |
Semenov Institute of Chemical Physics
|
| 2 |
Institute of Problems of Chemical Physics, Russian Academy of Sciences, Academician Semenov ave. 1, Chernogolovka 142432, Moscow Region, Russia
|
| 3 |
Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
|
| 4 |
Yuri Gagarin State Technical University of Saratov, Politechnicheskaya st. 77, Saratov 410054, Russia
|
| 5 |
Lomonosov Moscow State University, Leninskie gory 1, Moscow 119991, Russia
|
| 6 |
Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygina st. 4, Moscow 119991, Russia
|
| 7 |
Boreskov Institute of Catalysis, Siberian Branch of Russian Academy of Sciences, pr. Akad. Lavrentieva 5, Novosibirsk 630090, Russia
|
| 8 |
Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia
|
|
Информация о финансировании (4)
|
1
|
Российский научный фонд
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16-13-00112
|
|
2
|
Федеральное агентство научных организаций России
|
0082-2014-0011 (АААА-А17-117111600093-8)
|
|
3
|
Российский фонд фундаментальных исследований
|
16-03-00143 (АААА-А16-116031050045-0)
|
|
4
|
Российский фонд фундаментальных исследований
|
19-03-00358 (АААА-А19-119031290055-2)
|
Electrical conduction and oxygen diffusion mobility in the bixbyite (Ia3̅) and rhombohedral (R3̅) polymorphs of the Ln6MoO12−Δ (Ln = Er, Tm, Yb; Δ = δ, δ1, δ2; δ1 > δ2) heavy lanthanide molybdates, belonging to new, previously unexplored classes of potential mixed (ionic–electronic) conductors, have been studied in the range of 200–900 °C. The oxygen self-diffusion coefficient in bixbyite (Ia3̅) Yb6MoO12−δ phase estimated by the temperature-programmed heteroexchange with C18O2 was shown to be much higher than that for rhombohedral (R3̅) RI (with large oxygen deficiency) and (R3̅) RII (with small oxygen deficiency) Ln6MoO12−Δ (Ln = Tm, Yb; Δ = δ1; δ1 > δ2) oxides. According to the activation energy for total conduction in ambient air, 0.99, 0.93, and 1.01 eV in Er6MoO12−δ, Tm6MoO12−δ, and Yb6MoO12−δ bixbyites, respectively, oxygen ion conductivity prevails in the range ∼200–500 °C. Oxygen mobility data for the rhombohedral Ln6MoO12−Δ (Ln = Er, Tm, Yb; Δ = δ1, δ2) phases RI and RII indicate that the oxygen in these phases exhibits mobility at much higher temperatures, such as those above 600–700 °C. Accordingly, below 600–700 °C they have predominantly electronic conductivity. As shown by total conductivity study of Ln6MoO12−δ (Ln = Er, Tm, Yb) bixbyites (Ia3̅) and rhombohedral phases Ln6MoO12−Δ (Ln = Er, Tm, Yb; Δ = δ1, δ2) (R3̅) in dry and wet air, the proton conductivity contribution exists only in Ln6MoO12−δ (Ln = Er, Tm, Yb) bixbyites up to 450–600 °C and decreases with a decreasing of the lanthanide ionic radius. The obtained data on the mobility of oxygen and the presence of proton contribution in bixbyites in the 300–600 °C temperature range make it possible to confirm unequivocally that Ln6MoO12−δ (Ln = Er, Tm, Yb) bixbyites are mixed electron–proton conductors at these temperatures.