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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 1; Hansen, Anna-Lena 3; Saraci, Erisa 1,2; Ras, Erik-Jan; Behrens, Malte; Studt, Felix 1,2; Grunwaldt, Jan-Dierk 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


Verlagsausgabe §
DOI: 10.5445/IR/1000135425
Veröffentlicht am 28.11.2021
Originalveröffentlichung
DOI: 10.1002/cctc.202100692
Scopus
Zitationen: 5
Web of Science
Zitationen: 5
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Zitationen: 5
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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
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