In Situ Study of Catalytic Processes: Neutron Diffraction of a Methanol Synthesis Catalyst at Industrially Relevant Pressure

Kandemir, Timur; Girgsdies, Frank; Hansen, Thomas C.; Liss, Klaus-Dieter; Kasatkin, Igor; Kunkes, Edward L.; Wowsnick, Gregor; Jacobsen, Nikolas; Schlögl, Robert; Behrens, Malte

doi:10.1002/anie.201209539

Cited by 74 publications

(80 citation statements)

References 49 publications

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“…Previous studies by Kandemir et al [27] suggested the formation of mobile ZnO x species in such high performance catalysts, but also in model type catalysts mobile ZnO species were reported previously. [28] A reduction of the strong Cu/ZnO interaction could easily occur by retraction of mobile ZnO, which is supported by the observed crystallization of ZnO and ZnAl 2 O 4 in the presented catalysts during the deactivation period.…”

Section: Discussionmentioning

confidence: 52%

“…As poisoning of the catalysts was excluded from the experiments and the maximum temperature of 553 K is too low for bulk formation of brass, the deactivation achieved in this work results most likely from a reduction of the active site concentration. [27] Considering further the significant drop in active phase surface area (figure 5), the sintering of copper particles appears to be the main source of catalyst deactivation at a first glance. Although this feature would be applicable for many supported metal catalysts, in this case severe restrictions have to be made: The active phase surface area (classically determined by N 2 O-RFC), does not represent the actual metallic copper surface area but a combination of the metallic surface area and oxophilic sites at the Cu/ZnO interface.…”

Section: Discussionmentioning

confidence: 98%

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Kinetics of deactivation on Cu/ZnO/Al2O3 methanol synthesis catalysts

Fichtl

Schlereth

Jacobsen

et al. 2015

Applied Catalysis A: General

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Section: Discussionmentioning

confidence: 52%

Section: Discussionmentioning

confidence: 98%

Kinetics of deactivation on Cu/ZnO/Al2O3 methanol synthesis catalysts

Fichtl

Schlereth

Jacobsen

et al. 2015

Applied Catalysis A: General

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242

192

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“…This is supported by a recent in situ neutron diffraction investigation of a commercial Cu-ZnO-Al 2 O 3 catalyst under mixed syngas (R = 57) at 523 K and 6.0 MPa, i.e., under similar conditions to those used in our study. 59 3.3. Tuning the Interaction between Cu and ZnO.…”

Section: −1mentioning

confidence: 99%

Zinc-Rich Copper Catalysts Promoted by Gold for Methanol Synthesis

et al. 2015

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In this study, we gathered further understanding of the function of the components in the Cu-ZnOAl 2 O 3 catalyst for methanol synthesis from mixed syngas feeds (CO/CO 2 /H 2 ) to rationally develop systems displaying superior performance. In order to unravel the role of ZnO in the hydrogenation of the preferred methanol source, CO 2 , and in the (reverse) water−gas shift ((R)WGS) reaction, we tested coprecipitated materials with variable surface zinc content under industrially relevant conditions (5.0 MPa, 503−543 K). We found that a surface enrichment in zinc leads to higher activity and selectivity due to (i) the enhancement of the unique synergistic Cu-ZnO interactions boosting CO 2 hydrogenation, (ii) the inhibition of the RWGS reaction which produces the undesired CO, and (iii) the electronic stabilization of the Cu sites against reoxidation by CO 2 or H 2 O. Thus, a catalyst with a surface Zn/(Cu + Zn) ratio of 0.8 displayed superior catalytic properties than a commercial benchmark sample, which featured only half of the ratio. An even more performing catalyst was obtained utilizing oxalates instead of hydroxycarbonates as precursors. The better thermal degradation of the former minimizes the content of residual carbon on the surface of the activated catalyst improving the amount of Cu-ZnO contacts. The retention of the metallic state of copper was greatly favored by the deposition of an electron-withdrawing metal such as gold. The Cu-based activity in mixed syngas and CO 2 hydrogenation of the zinc-rich gold-promoted catalyst was ca. 2 and 4 times higher, respectively, than that of the commercial system.

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“…The long-known ''synergy'' [102][103][104][105] between Cu and its ''support'' ZnO leads to active sites comprising Cu, Zn and oxygen in unknown stoichiometric and structural relations. We know that the active catalyst carries an overgrowth of a metastable form of ZnO [106] sitting on a copper surface that is activated by structural defects creating surface steps [107][108][109]. It is more than unlikely that such a complicated functional structure of a high-performance catalyst [110] can be described in any meaningful form by a perfect Cu metal surface model.…”

Section: The Chemical Toolbox Of Cecmentioning

confidence: 99%

Sustainable Energy Systems: The Strategic Role of Chemical Energy Conversion

Schlögl

2016

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In our globalized economy a multitude of energy systems are in operation. They present quite different structures and targets despite their common goal of supplying the energy needs for all societal activities reflecting the different boundary conditions of respective societies. The common quest for sustainability has given renewable electricity and ''solar fuels'' a high attention. The paper describes some underlying systemic aspects of integrating renewable with fossil energy and makes the point that without chemical energy conversion (CEC) this target will not be possible. A non-exhaustive list of grand challenges in CEC is derived. Some aspects of chemical energy science are discussed.

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In Situ Study of Catalytic Processes: Neutron Diffraction of a Methanol Synthesis Catalyst at Industrially Relevant Pressure

Cited by 74 publications

References 49 publications

Kinetics of deactivation on Cu/ZnO/Al2O3 methanol synthesis catalysts

Kinetics of deactivation on Cu/ZnO/Al2O3 methanol synthesis catalysts

Zinc-Rich Copper Catalysts Promoted by Gold for Methanol Synthesis

Sustainable Energy Systems: The Strategic Role of Chemical Energy Conversion

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