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Title: IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

Abstract

Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy. Nano-structured, mainly metallic copper was detected on the surface of the Cu/MgO catalyst. In contrast, the high energy of the main peak in the spectrum of CO adsorbed on reduced Cu/ZnO:Al (2125 cm -1) proves that metallic copper is largely absent on the surface of this catalyst. The band is assigned to Zn δ+–CO. The presence of not completely reduced Cu δ+–CO species cannot be excluded. The results are interpreted in terms of a partial coverage of the copper nano-particles in the Cu/ZnO:Al catalyst by a thin layer of metastable, defective zinc oxide. Minor contributions in the spectrum at 2090 and 2112 cm -1 due to nano-structured Cu 0–CO and CO adsorbed on highly defective Cu 0, respectively, indicate that the coverage of metallic copper is not complete.

Authors:
 [1];  [2];  [2];  [3];  [2]
  1. Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany). Department of Inorganic Chemistry; Stanford Univ., CA (United States). Department of Chemical Engineering; SLAC National Accelerator Lab., Menlo Park, CA (United States). SUNCAT Center for Interface Science and Catalysis
  2. Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany). Department of Inorganic Chemistry
  3. Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany). Department of Inorganic Chemistry ; Max Planck Institute for Chemical Energy Conversion, Mulheim (Germany)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1417300
Grant/Contract Number:
AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Topics in Catalysis
Additional Journal Information:
Journal Volume: 60; Journal Issue: 19-20; Journal ID: ISSN 1022-5528
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Cu; Methanol synthesis catalyst; CO adsorption; DRIFTS

Citation Formats

Schumann, Julia, Kröhnert, Jutta, Frei, Elias, Schlögl, Robert, and Trunschke, Annette. IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer. United States: N. p., 2017. Web. doi:10.1007/s11244-017-0850-9.
Schumann, Julia, Kröhnert, Jutta, Frei, Elias, Schlögl, Robert, & Trunschke, Annette. IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer. United States. doi:10.1007/s11244-017-0850-9.
Schumann, Julia, Kröhnert, Jutta, Frei, Elias, Schlögl, Robert, and Trunschke, Annette. Mon . "IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer". United States. doi:10.1007/s11244-017-0850-9. https://www.osti.gov/servlets/purl/1417300.
@article{osti_1417300,
title = {IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer},
author = {Schumann, Julia and Kröhnert, Jutta and Frei, Elias and Schlögl, Robert and Trunschke, Annette},
abstractNote = {Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy. Nano-structured, mainly metallic copper was detected on the surface of the Cu/MgO catalyst. In contrast, the high energy of the main peak in the spectrum of CO adsorbed on reduced Cu/ZnO:Al (2125 cm-1) proves that metallic copper is largely absent on the surface of this catalyst. The band is assigned to Znδ+–CO. The presence of not completely reduced Cuδ+–CO species cannot be excluded. The results are interpreted in terms of a partial coverage of the copper nano-particles in the Cu/ZnO:Al catalyst by a thin layer of metastable, defective zinc oxide. Minor contributions in the spectrum at 2090 and 2112 cm-1 due to nano-structured Cu0–CO and CO adsorbed on highly defective Cu0, respectively, indicate that the coverage of metallic copper is not complete.},
doi = {10.1007/s11244-017-0850-9},
journal = {Topics in Catalysis},
number = 19-20,
volume = 60,
place = {United States},
year = {Mon Aug 28 00:00:00 EDT 2017},
month = {Mon Aug 28 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 2works
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  • The results of kinetic tests and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) show the important role played by a ZnO–copper interface in the generation of CO and the synthesis of methanol from CO 2 hydrogenation. The deposition of nanoparticles of ZnO on Cu(100) and Cu(111), θ oxi < 0.3 monolayer, produces highly active catalysts. The catalytic activity of these systems increases in the sequence: Cu(111) < Cu(100) < ZnO/Cu(111) < ZnO/Cu(100). The structure of the copper substrate influences the catalytic performance of a ZnO–copper interface. Furthermore, size and metal–oxide interactions affect the chemical and catalytic properties of the oxide making themore » supported nanoparticles different from bulk ZnO. The formation of a ZnO–copper interface favors the binding and conversion of CO 2 into a formate intermediate that is stable on the catalyst surface up to temperatures above 500 K. Alloys of Zn with Cu(111) and Cu(100) were not stable at the elevated temperatures (500–600 K) used for the CO 2 hydrogenation reaction. However, reaction with CO 2 oxidized the zinc, enhancing its stability over the copper substrates.« less
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  • The greenhouse effect of carbon dioxide has been recognized to be one of the most serious problems in the world, and a number of countermeasures have been proposed so far. Catalytic hydrogenation of CO{sub 2} to produce various kinds of chemicals and fuels has received much attention as one of the most promising mitigation options. In particular, methanol synthesis by CO{sub 2} hydrogenation has been considered to play an important role in the transportation of hydrogen energy produced from natural energy such as solar energy, hydropower and so on. According to some estimations, an electric power of 300 MWh couldmore » be obtained from a methanol fired power plant in Japan, if methanol synthesized from CO{sub 2} and H{sub 2} produced by a electrolysis of water using an electric power of 1000 MWh is transported to Japan through the system. A practical methanol synthesis process greatly requires a high performance catalyst, which must be highly active and selective for methanol synthesis and also stable for a long period in a continuous operation. NIRE and RITE have been doing a joint research on methanol synthesis by catalytic hydrogenation of carbon dioxide. The authors have elucidated the role of metal oxides contained in Cu/ZnO-based ternary catalysts, and then developed Cu/ZnO-based multicomponent catalysts containing two or three metal oxides. Furthermore, we have examined the change in the activity of the multicomponent catalysts during a long term methanol synthesis test, and investigated the methanol synthesis over the multicomponcnt catalysts by using a reactor with a recycling equipment for unreacted gases.« less
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