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Cu−Zn Alloy Formation as Unfavored State for Efficient Methanol Catalysts
Author(s) -
Frei Elias,
Gaur Abhijeet,
Lichtenberg Henning,
Zwiener Leon,
Scherzer Michael,
Girgsdies Frank,
Lunkenbein Thomas,
Schlögl Robert
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202000777
Subject(s) - alloy , catalysis , materials science , x ray absorption spectroscopy , chemical engineering , methanol , copper , absorption spectroscopy , transmission electron microscopy , heterogeneous catalysis , oxidation state , inorganic chemistry , nanotechnology , chemistry , metallurgy , organic chemistry , physics , quantum mechanics , engineering
The active sites of Cu/ZnO‐based catalysts, commercially applied for the hydrogenation of CO 2 or CO 2 ‐rich synthesis gas, are still subject of current debates. Generally, the discussion is focused on the nature of the interfacial contact between Cu and ZnO, particularly whether it is rather of oxidic (Cu−ZnO) or alloying (Cu−Zn) character. We report on kinetic investigations on a Cu/ZnO : Al high performance catalyst activated at different temperatures. Incrementally increasing temperature under reductive conditions leads also to increased CuZn‐alloy formation, analyzed by in‐situ X‐ray diffraction, in‐situ X‐ray absorption spectroscopy and high resolution transmission electron microscopy. The combination of the catalytic data and the complementary characterization techniques provide valuable insights on the relevant reaction sites for CH 3 OH formation. Our results highlight the complexity of the interfacial contact with evidence for Cu−ZnO reaction sites and clarify the negative impact of CuZn alloy formation on the nature of the active site.