A high-pressure reaction chamber for in situ EXAFS spectroscopy of catalysts

Neils, Thomas L.; Burlitch, James M.

doi:10.1016/0021-9517(89)90302-3

“…XPS spectra of fully reduced ternary catalysts do not reveal any signs of Cu + [261]. The sensitivity has been estimated as 2% of Cu + on a catalyst weight basis [173,[262][263][264][265][266][267]. EXAFS studies on ternary catalysts also have not shown any Cu + [114].…”

Section: Reaction Mechanism(s) and Active Sitesmentioning

confidence: 99%

Methanol Synthesis

Hansen¹,

Nielsen²

2008

Handbook of Heterogeneous Catalysis

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The sections in this article are Introduction Thermodynamics Methanol Synthesis Catalysts Introduction Zn O / Cr 2 O 3 Catalyst Copper‐Based Catalysts Cu / Zn O + Element ( Al , Cr , … ) Promotion of Cu / Zn O / MOx Catalysts Cu / Zr O 2 Other Cu , Cu / Me , Cu / Me Ox Catalysts Pd ‐Based Catalysts Sulfide Catalysts Other Catalysts Activation of Cu / Zn Catalyst Activity as a Function of the Nature of Copper‐Based Catalysts Catalyst Deactivation Sintering Sulfur Poisoning Other Poisons By‐Product Formation Reaction Mechanism(s) and Active Sites Cu + in a Zn O Matrix as the Active Center The S chottky Junction Theory Partly Oxidized Copper Independent of Support as Active Sites Metallic Copper in Dynamic Interaction with the Support Cu –Zinc Surface Alloy Model Water Gas Shift Reaction Kinetics Reaction Rate Equations Diffusion Restrictions Kinetics in Slurry Phase Methanol Synthesis Methanol Synthesis Technology Synthesis Gas Preparation Natural Gas Reforming Adiabatic Pre‐Reforming Tubular, Fired Reforming Autothermal Reforming and Oxygen‐Fired Secondary Reforming Gasification of Heavy Oil, Coal or Biomass Coproduction in Ammonia Plants and Use of Off‐gases Economics of Synthesis Gas Preparation Reactor Systems and Synthesis Loop Layout Slurry Phase Reactor Types Methanol Purification Concepts Circumventing the Equilibrium Limitations Other Methanol Synthesis Routes and Technologies Methanol Synthesis by Methane Activation Conclusion

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“…The cell body was modeled after designs [9][10][11][12] that reduce the void volume around the sample relative to those of other designs. 8,[13][14][15][16][17] To allow fluorescence detection, the plates holding the windows in place had to be thin, as reported in previous designs, [9][10][11]18 although not all of these are used for fluorescence detection. 9,11,19 No cell has been reported to operate well both under vacuum or gas-flow conditions.…”

Section: Cell Designmentioning

confidence: 99%

Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

Hoffman

¹

,

Debefve

²

,

Bendjeriou‐Sedjerari

³

et al. 2016

Review of Scientific Instruments

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X-ray absorption spectroscopy is an element-specific technique for probing the local atomic-scale environment around an absorber atom. It is widely used to investigate the structures of liquids and solids, being especially valuable for characterization of solid-supported catalysts. Reported cell designs are limited in capabilities—to fluorescence or transmission and to static or flowing atmospheres, or to vacuum. Our goal was to design a robust and widely applicable cell for catalyst characterizations under all these conditions—to allow tracking of changes during genesis and during operation, both under vacuum and in reactive atmospheres. Herein, we report the design of such a cell and a demonstration of its operation both with a sample under dynamic vacuum and in the presence of gases flowing at temperatures up to 300 °C, showing data obtained with both fluorescence and transmission detection. The cell allows more flexibility in catalyst characterization than any reported.

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“…Lastly, in our consideration of the development of in situ XAS to the nature and behavior of the CZA system during the 1980s, is the report due to Neils and Burtlich. 86 This is, in essence, a technical paper centered upon their attempts to go beyond in situ and to study the CZA system under what we would now know as "operando" conditions. This is to say they also wished to measure the structural properties of the CZA system at the sorts of pressures (50−100 bar), as well as temperatures, at which the commercial process is operated.…”

Section: −1989mentioning

confidence: 99%

“…This further underlines, and with the use of very surface sensitive tools, that copper is not oxidized by the application of a catalytic feed, and that oxidation observed by XPS in postreaction setups could be a result of oxidation during the sample transfer or evacuation, as was already observed in the 1980s. 73,74,86,473 Further, the carbon containing surface species could also be measured and interpreted. The results underlined the existing opinion, that formates dominate the surface in a CO 2 -containing feed, while methoxy species are mainly present in CO/H 2 .…”

Section: Determination Of the Catalyst Structurementioning

confidence: 99%

The Enigma of Methanol Synthesis by Cu/ZnO/Al₂O₃-Based Catalysts

Beck,

Newton,

van de Water

et al. 2024

Chem. Rev.

23

0

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The activity and durability of the Cu/ZnO/Al 2 O 3 (CZA) catalyst formulation for methanol synthesis from CO/CO 2 /H 2 feeds far exceed the sum of its individual components. As such, this ternary catalytic system is a prime example of synergy in catalysis, one that has been employed for the large scale commercial production of methanol since its inception in the mid 1960s with precious little alteration to its original formulation. Methanol is a key building block of the chemical industry. It is also an attractive energy storage molecule, which can also be produced from CO 2 and H 2 alone, making efficient use of sequestered CO 2 . As such, this somewhat unusual catalyst formulation has an enormous role to play in the modern chemical industry and the world of global economics, to which the correspondingly voluminous and ongoing research, which began in the 1920s, attests. Yet, despite this commercial success, and while research aimed at understanding how this formulation functions has continued throughout the decades, a comprehensive and universally agreed upon understanding of how this material achieves what it does has yet to be realized. After nigh on a century of research into CZA catalysts, the purpose of this Review is to appraise what has been achieved to date, and to show how, and how far, the field has evolved. To do so, this Review evaluates the research regarding this catalyst formulation in a chronological order and critically assesses the validity and novelty of various hypotheses and claims that have been made over the years. Ultimately, the Review attempts to derive a holistic summary of what the current body of literature tells us about the fundamental sources of the synergies at work within the CZA catalyst and, from this, suggest ways in which the field may yet be further advanced.

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A high-pressure reaction chamber for in situ EXAFS spectroscopy of catalysts

Cited by 24 publications

References 7 publications

Methanol Synthesis

Methanol Synthesis

Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

The Enigma of Methanol Synthesis by Cu/ZnO/Al₂O₃-Based Catalysts

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A high-pressure reaction chamber for in situ EXAFS spectroscopy of catalysts

Cited by 24 publications

References 7 publications

Methanol Synthesis

Methanol Synthesis

Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

The Enigma of Methanol Synthesis by Cu/ZnO/Al2O3-Based Catalysts

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The Enigma of Methanol Synthesis by Cu/ZnO/Al₂O₃-Based Catalysts