Ab initio study of CO2 hydrogenation mechanisms on inverse ZnO/Cu catalysts

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  • Thomas Reichenbach, Univ Freiburg, University of Freiburg, Freiburger Mat Forschungszentrum
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  • Krishnakanta Mondal, Univ Freiburg, University of Freiburg, Freiburger Mat Forschungszentrum
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  • Marc Jaeger, Univ Freiburg, University of Freiburg, Inst Anorgan & Analyt Chem
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  • Thomas Vent-Schmidt, Univ Freiburg, University of Freiburg, Inst Anorgan & Analyt Chem
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  • Daniel Himmel, Univ Freiburg, University of Freiburg, Inst Anorgan & Analyt Chem
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  • Valentin Dybbert, Univ Freiburg, University of Freiburg, Inst Anorgan & Analyt Chem
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  • Albert Bruix
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  • Ingo Krossing, Univ Freiburg, University of Freiburg, Inst Anorgan & Analyt Chem
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  • Michael Walter, Univ Freiburg, University of Freiburg, Phys Inst
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  • Michael Moseler, Univ Freiburg, University of Freiburg, Phys Inst

Methanol formation from CO2 and molecular hydrogen on ZnO/Cu catalysts is studied by gradient corrected density functional theory. The catalytically active region is modeled as a minimum size inverse catalyst represented by ZnxO gamma(H) clusters of different size and a ZnO nano-ribbon on an extended Cu (1 1 1) surface. These systems are chosen as a representative of thermodynamically stable catalyst structures under typical reaction conditions. Comparison to a high level wave function method reveals that density functional theory systematically underestimates reaction barriers, but nevertheless conserves their energetic ordering. In contrast to other metal-supported oxides like ceria and zirconia, the reaction proceeds through the formation of formate on ZnOx/Cu, thus avoiding the CO intermediate. The difference between the oxides is attributed to variance in the initial activation of CO2. The energetics of the formate reaction pathway is insensitive to the exact environment of undercoordinated Zn active sites, which points to a general mechanism for Cu-Zn based catalysts. (C) 2018 Elsevier Inc. All rights reserved.

Original languageEnglish
JournalJournal of Catalysis
Volume360
Pages (from-to)168-174
Number of pages7
ISSN0021-9517
DOIs
Publication statusPublished - Apr 2018

    Research areas

  • Inverse catalyst, methanol, CO2, Renewable energy, hydrogenation, DFT, Coupled cluster, TRANSITION-METAL SURFACES, DENSITY-FUNCTIONAL THEORY, METHANOL SYNTHESIS, CU/ZNO CATALYSTS, INTERACTION ENERGIES, SUPPORT INTERACTIONS, BENCHMARK DATABASE, CARBON-DIOXIDE, IONIC LIQUIDS, CONVERSION

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