Metal–Support Interactions in Cobalt-Aluminum co-Precipitated Catalysts: XPS and CO Adsorption Studies
Научная публикация
| Общее |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Оригинальная
|
| Журнал |
Journal of Molecular Catalysis A: Chemical
ISSN: 1381-1169
|
| Вых. Данные |
Год: 2001,
Том: 175,
Номер: 1-2,
Страницы: 189-204
Страниц
: 6
DOI:
10.1016/S1381-1169(01)00216-3
|
| Ключевые слова |
Alumina, Carbon monoxide, Cobalt, Metal-support interaction, XPS |
| Авторы |
Khassin Alexander A.
1
,
Yurieva Tamara M.
1
,
Kaichev Vasiliy V.
1
,
Bukhtiyarov Valerii I.
1
,
Budneva Anna A.
1
,
Paukshtis Evgeniy A.
1
,
Parmon Valentin N.
1
|
| Организации |
| 1 |
Boreskov Institute of Catalysis, 5, Pr. Lavrentieva, Novosibirsk 630090, Russia
|
|
Cobalt-aluminum catalysts were prepared using either the precipitation of Co2+ in the presence of freshly prepared Zn-Al hydrotalcite (the promoted sample) or the co-precipitation of Co2+ and Al3+ (the unpromoted samples). The evolution of the initial hydrotalcite-like structure was monitored during its calcination and the reductive treatment by means of XPS. It was shown that at 480°C the reduction of the calcined samples results in the formation of Co0 species, the further reduction at 650°C results in an increase of the amount of the Co0 species. The samples reduced at 650°C chemisorb readily carbon monoxide at 77 K, while the sample reduced at 480°C does not chemisorb CO at 77 K. At elevated temperatures, all reduced samples are found to be able to chemisorb CO. Terminal CO moieties as well as monodentate carbonates, formates and carboxyl species were detected at the surface of the reduced samples at their exposure to the CO medium at the elevated temperature. The intensity of the IR absorption bands of chemisorbed CO are found proportional to the surface fraction of the Co0 species, measured by XPS. The apparent red shift of the IR absorption bands is observed for CO adsorbed on the samples reduced at 480°C. The obtained data correlate with the catalytic properties of the Co-Al samples in hydrogenation reactions. The conclusion on the existence of a strong metal–support interaction in the samples under the study is made.