Deactivation of Au/CeO2 catalysts during CO oxidation: Influence of pretreatment and reaction conditions
PBN-AR
Instytucja
Instytut Fizyki Jądrowej im. Henryka Niewodniczańskiego Polskiej Akademii Nauk
Informacje podstawowe
Główny język publikacji
en
Czasopismo
JOURNAL OF CATALYSIS
ISSN
0021-9517
EISSN
Wydawca
DOI
URL
Rok publikacji
2016
Numer zeszytu
Strony od-do
160-179
Numer tomu
341
Identyfikator DOI
Liczba arkuszy
Autorzy
(liczba autorów: 6)
Pozostali autorzy
+ 5
Słowa kluczowe
en
Au catalyst
Au/CeO2
Catalyst pretreatment
CO oxidation
Deactivation
DRIFTS
XAS
XPS
Streszczenia
Język
en
Treść
The influence of the pretreatment on the activity and deactivation behavior of a high surface area 4.5 wt.% Au/CeO2 catalyst during low temperature CO oxidation reaction (Treact = 80 °C) was studied in a multi-technique approach. Furthermore, the influence of changing from a close-to-stoichiometric (1% CO, 1% O2 rest N2), to O2-rich (1% CO, 5% O2 rest N2) and CO-rich (5% CO, 1% O2 rest N2) gas mixtures was investigated. Findings from kinetic and deactivation measurements are correlated with experimental data on the Au particle size, Au and Ce oxidation state, and on the nature of adsorbed species after the different pretreatments and during/after subsequent reaction, which were obtained by operando and in situ methods such as operando X-ray absorption spectroscopy and IR spectroscopy, as well as ex situ X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. These data revealed that the pretreatment significantly affects catalyst structure, surface composition and activity in the initial stages of the reaction. During reaction, however, the catalyst surface composition approaches a dynamic equilibrium state, which is largely reached already after 10 min time on stream and which is independent of the pretreatment. Consequently, under present reaction conditions, longer-term deactivation is not dominated by the buildup of site blocking adsorbed species such as surface carbonates, but by slow processes such as reduction/re-oxidation of the bulk support during the reaction in combination with a modest irreversible Au NP growth.
Cechy publikacji
peer-reviewed
original-article
Inne
System-identifier
25969
CrossrefMetadata from Crossref logo
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