TY - JOUR
T1 - Structural Evolution of Copper-Oxo Sites in Zeolites upon the Reaction with Methane Investigated by Means of Cu K-edge X-ray Absorption Spectroscopy
AU - Artsiusheuski, Mikalai A.
AU - Safonova, Olga
AU - Palagin, Dennis
AU - van Bokhoven, Jeroen A.
AU - Sushkevich, Vitaly L.
N1 - Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
PY - 2023
Y1 - 2023
N2 - The structure of copper sites formed under an oxidative environment and their evolution in the course of the reaction with methane at elevated temperature was investigated by means of Cu K-edge X-ray absorption spectroscopy for a series of copper-containing MFI, MOR, and FAU zeolites. The pretreatment in oxygen at 723 K leads to the formation of copper(II)-oxo sites, whose nature depends on the framework type. Dimeric species are formed in CuMFI material, dimeric and monomeric sites coexist in CuMOR, and agglomerated copper-oxo nanoclusters are found in large-pore copper-containing faujasite (CuFAU). For all studied materials, the reaction with methane resulted in the exclusive formation of copper(I) species; no formation of metallic copper was detected even at 748 K. The nature of formed copper(I) species is governed by the structure of corresponding copper(II) centers. In particular, monomeric and dimeric copper(II)-oxo sites hosted in CuMOR and CuMFI are transformed into isolated copper(I) cations coordinated to ion-exchange positions of the zeolite. Contrarily, copper(II)-oxo clusters present in CuFAU undergo restructuring with only a partial loss of extra-framework oxygen and form aggregated species with a structure similar to that of bulk copper(I) oxide.
AB - The structure of copper sites formed under an oxidative environment and their evolution in the course of the reaction with methane at elevated temperature was investigated by means of Cu K-edge X-ray absorption spectroscopy for a series of copper-containing MFI, MOR, and FAU zeolites. The pretreatment in oxygen at 723 K leads to the formation of copper(II)-oxo sites, whose nature depends on the framework type. Dimeric species are formed in CuMFI material, dimeric and monomeric sites coexist in CuMOR, and agglomerated copper-oxo nanoclusters are found in large-pore copper-containing faujasite (CuFAU). For all studied materials, the reaction with methane resulted in the exclusive formation of copper(I) species; no formation of metallic copper was detected even at 748 K. The nature of formed copper(I) species is governed by the structure of corresponding copper(II) centers. In particular, monomeric and dimeric copper(II)-oxo sites hosted in CuMOR and CuMFI are transformed into isolated copper(I) cations coordinated to ion-exchange positions of the zeolite. Contrarily, copper(II)-oxo clusters present in CuFAU undergo restructuring with only a partial loss of extra-framework oxygen and form aggregated species with a structure similar to that of bulk copper(I) oxide.
UR - http://www.scopus.com/inward/record.url?scp=85160710935&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.3c01496
DO - 10.1021/acs.jpcc.3c01496
M3 - Article
AN - SCOPUS:85160710935
SN - 1932-7447
VL - 127
SP - 9603
EP - 9615
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 20
ER -