Oxidation of methane to methanol over Cu-exchanged zeolites: Scientia gratia scientiae or paradigm shift in natural gas valorization?

Jovanović, Zoran; Lange, Jean‐Paul; Ravi, Manoj; Knorpp, Amy J.; Sushkevich, Vitaly L.; Newton, Mark A.; Palagin, Dennis; Bokhoven, Jeroen A. van

doi:10.1016/j.jcat.2020.02.001

Cited by 45 publications

(80 citation statements)

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“…Successful partial oxidation of methane using oxygen relies not only on the storing of oxygen at the active extra‐framework copper site, but also on the ability of the zeolite framework to stabilize that active site while simultaneously preventing over‐oxidization of the product methanol. This can occur very selectively in copper‐zeolites, but productivity remains insufficient for industrial implementation [9] . Therefore, a detailed understanding of the active site upon activation in oxygen and of its structure‐property relationships are critical to the development of more active and productive materials.…”

Section: Figurementioning

confidence: 99%

Paired Copper Monomers in Zeolite Omega: The Active Site for Methane‐to‐Methanol Conversion

et al. 2021

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The direct conversion of methane to methanol using oxygen is a challenging but potentially rewarding pathway towards utilizing methane. By using a stepwise chemical looping approach, copper‐exchanged zeolites can convert methane to methanol, but productivity is still too low for viable implementation. However, if the nature of the active site could be elucidated, that information could be used to design more effective catalysts. By employing anomalous X‐ray powder diffraction with support from theory and other X‐ray techniques, we have derived a quantitative and spatial description of the highly selective, active copper sites in zeolite omega (Cu‐omega). This is the first comprehensive description of the structure of non‐copper‐oxo active species and will provide a pivotal model for future development for materials for methane to methanol conversion.

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Section: Figurementioning

confidence: 99%

Paired Copper Monomers in Zeolite Omega: The Active Site for Methane‐to‐Methanol Conversion

et al. 2021

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“…This deficit notwithstanding, substantial improvements in CH 3 OH yield per chemical looping cycle have been achieved to reach the theoretical limit of CH 3 OH for two Cu II sites [18] . However, state‐of‐the‐art zeolite‐based materials remain economically unviable for commercial applications because of an insufficient amount of reactive sites per unit mass and the long cycle times associated with this step‐wise process [19, 20] . Thus, alternate materials must be explored for this challenging transformation.…”

Section: Introductionmentioning

confidence: 99%

Methane‐to‐Methanol on Mononuclear Copper(II) Sites Supported on Al₂O₃: Structure of Active Sites from Electron Paramagnetic Resonance**

et al. 2021

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The selective conversion of methane to methanol remains one of the holy grails of chemistry, where Cu‐exchanged zeolites have been shown promote this reaction under stepwise conditions. Over the years, several active sites have been proposed, ranging from mono‐, di‐ to trimeric CuII. Herein, we report the formation of well‐dispersed monomeric CuII species supported on alumina using surface organometallic chemistry and their reactivity towards the selective and stepwise conversion of methane to methanol. Extensive studies using various transition alumina supports combined with spectroscopic characterization, in particular electron paramagnetic resonance (EPR), show that the active sites are associated with specific facets, which are typically found in γ‐ and η‐alumina phase, and that their EPR signature can be attributed to species having a tri‐coordinated [(Al2O)CuIIO(OH)]− T‐shape geometry. Overall, the selective conversion of methane to methanol, a two‐electron process, involves two monomeric CuII sites that play in concert.

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“…17 However, state-of-the-art zeolite-based materials remain economically unviable for commercial applications because of an insufficient amount of reactive sites per unit mass and the long cycle times associated with this step-wise process. 18,19 Thus, alternate materials must be explored for this challenging transformation. Copper supported on silica produces CH3OH, [20][21][22] however the obtained yield is low and the active sites are ill-defined (small CuO clusters).…”

Section: Introductionmentioning

confidence: 99%

CH4-to-CH3OH on Mononuclear Cu(II) Sites Supported on Al2O3: Structure of Active Sites from Electron Paramagnetic Resonance

Meyet¹,

Ashuiev²,

Noh³

et al. 2021

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The selective conversion of methane to methanol remains one of the holy grails of chemistry, where Cu-exchanged zeolites have been shown to selectively convert methane to methanol under stepwise conditions. Over the years, several active sites have been proposed, ranging from mono-, di- to trimeric Cu(II). Herein, we report the formation of well-dispersed monomeric Cu(II) species supported on alumina using surface organometallic chemistry and their reactivity towards the selective and stepwise conversion of methane to methanol. Extensive studies using various transition alumina supports combined with spectroscopic characterization, in particular electron paramagnetic resonance (EPR), show that the active sites are associated with specific facets, which are typically found in gamma- and eta-alumina phase, and that their EPR signature can be attributed to species having a tri-coordinated [(Al2O)CuIIO(OH)]-,T-shape geometry. Overall, the selective conversion of methane to methanol, a two-electron process, involve two of these isolated monomeric Cu(II) sites that play in concert.

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Oxidation of methane to methanol over Cu-exchanged zeolites: Scientia gratia scientiae or paradigm shift in natural gas valorization?

Cited by 45 publications

References 82 publications

Paired Copper Monomers in Zeolite Omega: The Active Site for Methane‐to‐Methanol Conversion

Paired Copper Monomers in Zeolite Omega: The Active Site for Methane‐to‐Methanol Conversion

Methane‐to‐Methanol on Mononuclear Copper(II) Sites Supported on Al₂O₃: Structure of Active Sites from Electron Paramagnetic Resonance**

CH4-to-CH3OH on Mononuclear Cu(II) Sites Supported on Al2O3: Structure of Active Sites from Electron Paramagnetic Resonance

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Oxidation of methane to methanol over Cu-exchanged zeolites: Scientia gratia scientiae or paradigm shift in natural gas valorization?

Cited by 45 publications

References 82 publications

Paired Copper Monomers in Zeolite Omega: The Active Site for Methane‐to‐Methanol Conversion

Paired Copper Monomers in Zeolite Omega: The Active Site for Methane‐to‐Methanol Conversion

Methane‐to‐Methanol on Mononuclear Copper(II) Sites Supported on Al2O3: Structure of Active Sites from Electron Paramagnetic Resonance**

CH4-to-CH3OH on Mononuclear Cu(II) Sites Supported on Al2O3: Structure of Active Sites from Electron Paramagnetic Resonance

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Methane‐to‐Methanol on Mononuclear Copper(II) Sites Supported on Al₂O₃: Structure of Active Sites from Electron Paramagnetic Resonance**