New Reaction of Anion Radicals O− with Water on the Surface of FeZSM-5
Научная публикация
| Общее |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Оригинальная
|
| Журнал |
Journal of Catalysis
ISSN: 0021-9517
, E-ISSN: 1090-2694
|
| Вых. Данные |
Год: 2008,
Том: 254,
Номер: 1,
Страницы: 110-120
Страниц
: 11
DOI:
10.1016/j.jcat.2007.12.001
|
| Ключевые слова |
α-Oxygen, Anion radical O-, DRIFT spectroscopy, FeZSM-5, N2O, Photocatalytic oxidation |
| Авторы |
Panov Gennady I.
1
,
Starokon Eugeny V.
1
,
Pirutko Larisa V.
1
,
Paukshtis Eugeny A.
1
,
Parmon Valentin N.
1
|
| Организации |
| 1 |
Институт катализа им. Г.К. Борескова СО РАН
|
|
Информация о финансировании (2)
|
1
|
Российский фонд фундаментальных исследований
|
06-03-72551
|
|
2
|
Российский фонд фундаментальных исследований
|
06-03-33087
|
Complexes of bivalent iron stabilized in the FeZSM-5 zeolite matrix (α-sites) are known to be able to decompose nitrous oxide stoichiometrically to form oxygen anion radicals, O−, bound to iron (α-oxygen),
(FeII)α + N2O → (FeIIIsingle bondO−)α + N2.
Similar to O− radicals on V and Mo oxides, α-oxygen is highly reactive in respect to CO, H2, methane and other hydrocarbons. It participates in catalytic oxidation of benzene to phenol by nitrous oxide, providing selectivity close to 100%. In this work, adsorption measurements, IR spectroscopy, TPD, and isotope methods were used to describe an earlier unknown reaction of O− species with water, which proceeds at 5–200 °C via the hydrogen abstraction mechanism according to the equation 2(FeIIIsingle bondO−)α + H2O → 2(FeIIIsingle bondOH−)α + (1/2)O2.
The reaction leads to the hydroxyl groups formed on α-sites, and equivalent amount of O2 evolves into the gas phase from water. Desorption of the hydroxyl groups occurs at above 400 °C via their recombination into water and dioxygen, resulting in the reactivation of α-sites, 2(FeIIIsingle bondOH−)α → 2(FeII)α + H2O + (1/2)O2.
High sensitivity of α-oxygen to water admixtures may be an important factor explaining some contradictory results reported in the literature on the behavior of α-oxygen. Because α-oxygen is a typical representative of anion radicals O−, this reaction may be relevant not only to the conventional oxidation catalysis over zeolites and metal oxides, but also to photocatalytic processes, where formation of O− is well documented.