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Unravelling the Zn‐Cu Interaction during Activation of a Zn‐promoted Cu/MgO Model Methanol Catalyst

Pandit, Lakshmi 1,2; Boubnov, Alexey 1,2; Behrendt, Gereon; Mockenhaupt, Benjamin; Chowdhury, Chandra 1; Jelic, Jelena ORCID iD icon 1; Hansen, Anna-Lena 3; Saraci, Erisa ORCID iD icon 1,2; Ras, Erik-Jan; Behrens, Malte; Studt, Felix 1,2; Grunwaldt, Jan-Dierk ORCID iD icon 1,2
1 Institut für Katalyseforschung und -technologie (IKFT), Karlsruher Institut für Technologie (KIT)
2 Institut für Technische Chemie und Polymerchemie (ITCP), Karlsruher Institut für Technologie (KIT)
3 Karlsruher Institut für Technologie (KIT)

Abstract:

We report on an inverse model Cu/MgO methanol catalyst modified with 5 % zinc oxide at the Cu surface to element-specifically probe the interplay of metallic copper and zinc oxide during reductive activation. The structure of copper and zinc was unraveled by in situ X-ray diffraction (XRD) and in situ X-ray absorption spectroscopy (XAS) supported by theoretical modelling of the extended X-ray absorption fine structure and X-ray absorption near-edge structure spectra. Temperature-programmed reduction in H2 during in situ XAS showed that copper was reduced starting at 145 °C. With increasing reduction temperature, zinc underwent first a geometrical change in its structure, followed by reduction. The reduced zinc species were identified as surface alloy sites, which coexisted from 200 °C to 340 °C with ZnO species at the copper surface. At 400 °C Zn−Cu bulk-alloyed particles were formed. According to in situ XRD and in situ XAS, about half of the ZnO was not fully reduced, which can be explained by a lack of contact with copper. Our experimental results were further substantiated by density functional theory calculations, which verified that ZnO with neighboring Cu atoms reduced more easily. ... mehr

Zugehörige Institution(en) am KIT Institut für Angewandte Materialien – Energiespeichersysteme (IAM-ESS)
Institut für Angewandte Materialien (IAM)
Institut für Katalyseforschung und -technologie (IKFT)
Institut für Technische Chemie und Polymerchemie (ITCP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1867-3880, 1867-3899
KITopen-ID: 1000135425
HGF-Programm 38.03.02 (POF IV, LK 01) Power-based Fuels and Chemicals
Weitere HGF-Programme 56.98.01 (POF III, LK 01) Betrieb in MML
Erschienen in ChemCatChem
Verlag Wiley-VCH Verlag
Band 13
Heft 19
Seiten 4120-4132
Projektinformation SPP 2080; DynaKat-MeOH (DFG, DFG KOORD, GR 3987/14-1)
Vorab online veröffentlicht am 14.07.2021
Nachgewiesen in Scopus
Web of Science
Dimensions

Verlagsausgabe §
DOI: 10.5445/IR/1000135425
Veröffentlicht am 28.11.2021
Originalveröffentlichung
DOI: 10.1002/cctc.202100692
Scopus
Zitationen: 26
Web of Science
Zitationen: 23
Dimensions
Zitationen: 27
Seitenaufrufe: 152
seit 20.07.2021
Downloads: 282
seit 03.12.2021
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