Surface oxygen Vacancies on Reduced Co3 O4 (100): Superoxide Formation and Ultra-Low-Temperature CO Oxidation.
Angew Chem Int Ed Engl
; 60(30): 16514-16520, 2021 Jul 19.
Article
in En
| MEDLINE
| ID: mdl-33998763
ABSTRACT
The activation of molecular oxygen is a fundamental step in almost all catalytic oxidation reactions. We have studied this topic and the role of surface vacancies for Co3 O4 (100) films with a synergistic combination of experimental and theoretical methods. We show that the as-prepared surface is B-layer terminated and that mild reduction produces oxygen single and double vacancies in this layer. Oxygen adsorption experiments clearly reveal different superoxide species below room temperature. The superoxide desorbs below ca. 120â
K from a vacancy-free surface and is not active for CO oxidation while superoxide on a surface with oxygen vacancies is stable up to ca. 270â
K and can oxidize CO already at the low temperature of 120â
K. The vacancies are not refilled by oxygen from the superoxide, which makes them suitable for long-term operation. Our joint experimental/theoretical effort highlights the relevance of surface vacancies in catalytic oxidation reactions.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Angew Chem Int Ed Engl
Year:
2021
Document type:
Article
Affiliation country:
Germany