Methane activation by ZSM-5-supported transition metal centers

Kiani, Daniyal; Sourav, Sagar; Tang, Yadan; Baltrušaitis, Jonas; Wachs, Israel E.

doi:10.1039/d0cs01016b

Cited by 92 publications

(69 citation statements)

References 137 publications

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“…Over the past decade, the most significant success was accomplished in the oxidative coupling of methane (OCM) by Siluria and Linde-Engineering . Besides OCM, research activities on the non-oxidative methane dehydroaromatization (MDA), first achieved on Mo incorporated ZSM-5 catalyst by Wang et al in 1993, is currently also gaining momentum. ,− Aromatics, having vast applications (gasoline additives, detergents, dyes, insecticides etc. ), are mainly manufactured by crude oil refining in the modern chemical industry; however, MDA catalysis has a great potential to replace the existing processes since global natural gas (and biogas) production is increasing every year .…”

Section: Introductionmentioning

confidence: 99%

Illuminating the Intrinsic Effect of Water Co-feeding on Methane Dehydroaromatization: A Comprehensive Study

et al. 2021

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Among all catalytic natural gas valorization processes, methane dehydroaromatization (MDA) still has a great potential to be utilized at an industrial level. Although the use of Mo/H-ZSM-5 as an MDA catalyst was first reported almost three decades ago, the process is yet to be industrialized, because of its inherent challenges. In order to improve the overall catalytic performance and lifetime, the co-feeding of water constitutes a promising option, because of its abundance and nontoxicity. Although water's (limited) positive influence on catalyst lifetime has earlier been exhibited, the exact course of action (like mechanism or the water effect on active sites) is yet to be established. To bridge this knowledge gap, in this work, we have performed an in-depth investigation to elucidate the effects of water cofeeding over a well-dispersed Mo/H-ZSM-5 catalyst by using an array of advanced characterization techniques (nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry−temperature-programmed oxidation/mass spectroscopy (TG-TPO/MS), scanning transmission electron microscopy (STEM), N 2 physisorption, Raman spectroscopy, inductively coupled plasma−optical emission spectroscopy (ICP-OES)). Our results demonstrate that the addition of water results in the occurrence of steam reforming (of both coke and methane) in parallel to MDA. Moreover, the presence of water affects the reducibility of Mo sites, as corroborated with computational analysis to examine the state and locality of Mo sites under various water levels and transformation of the catalyst structure during deactivation. We anticipate that our comprehensive study of the structure−function relationship on Mo/H-ZSM-5 under humid MDA conditions will be beneficial for the development of future methane valorization technologies.

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Section: Introductionmentioning

confidence: 99%

Illuminating the Intrinsic Effect of Water Co-feeding on Methane Dehydroaromatization: A Comprehensive Study

et al. 2021

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“…Since then, various catalysts based on metal ions (Mo, Fe, Zn, Cr, V, W, etc.) dispersed on zeolites (e.g., ZSM-5, MCM-22, ZSM-8, MCM-49, and mordenite) have been developed and tested to improve MDR performance [44][45][46][47]. Detailed catalyst summary and design concept, as well as the suggested mechanism, will be elucidated in Sect.…”

Section: Nonoxidative Coupling Of Methane (Nocm) To C 2+mentioning

confidence: 99%

Introducing Methane Activation

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et al. 2021

Methane Activation and Utilization in the Petrochemical and Biofuel Industries

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“…[1] Thelow market value and high transportation cost of NG compared to liquid oil make NG afeedstock that is typically flared or burned to generate low value-added electricity and results in wastage of aprecious carbon resource generating tremendous amount of global warming CO 2 .C ost-effective conversion of NG into value-added chemical intermediates would lower its shipping cost and recover large quantities of NG currently being flared. [2] Thea bsence of thermodynamic limitations,h igh CH 4 conversion ( % 35-40 %) and high product selectivity ( % 70-80 %) of the single-step oxidative coupling of methane (OCM) to C 2 products have highlighted this process as ahighly promising natural gas (NG) conversion technology. [3] Among hundreds of catalysts investigated for the OCM reaction since its invention in early 80s, [4] thes upported Mn-Na 2 WO 4 /SiO 2 has been reported to be one of the most highly performing catalysts due to its long-term on-stream stability at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na₂WO₄/SiO₂ Catalysts

et al. 2021

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The complex structure of the catalytic active phase, and surface-gas reaction networks have hindered understanding of the oxidative coupling of methane (OCM) reaction mechanism by supported Na 2 WO 4 /SiO 2 catalysts.T he present study demonstrates,with the aid of in situ Raman spectroscopy and chemical probe (H 2 -TPR, TAPand steady-state kinetics) experiments,that the long speculated crystalline Na 2 WO 4 active phase is unstable and melts under OCM reaction conditions, partially transforming to thermally stable surface Na-WO x sites.K inetic analysis via temporal analysis of products (TAP) and steady-state OCM reaction studies demonstrate that (i)s urface Na-WO x sites are responsible for selectively activating CH 4 to C 2 H x and over-oxidizing CH y to CO and (ii) molten Na 2 WO 4 phase is mainly responsible for over-oxidation of CH 4 to CO 2 and also assists in oxidative dehydrogenation of C 2 H 6 to C 2 H 4 .These new insights reveal the nature of catalytic active sites and resolve the OCM reaction mechanism over supported Na 2 WO 4 /SiO 2 catalysts.

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Methane activation by ZSM-5-supported transition metal centers

Abstract: The literature on methane dehydroaromatization (MDA) to benzene using ZSM-5 supported, group V–VIII transition metal-based catalysts (MOx/ZSM-5) is critically reviewed with a focus on in situ and operando molecular insights.

Cited by 92 publications

References 137 publications

Illuminating the Intrinsic Effect of Water Co-feeding on Methane Dehydroaromatization: A Comprehensive Study

Illuminating the Intrinsic Effect of Water Co-feeding on Methane Dehydroaromatization: A Comprehensive Study

Introducing Methane Activation

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na₂WO₄/SiO₂ Catalysts

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Methane activation by ZSM-5-supported transition metal centers

Abstract: The literature on methane dehydroaromatization (MDA) to benzene using ZSM-5 supported, group V–VIII transition metal-based catalysts (MOx/ZSM-5) is critically reviewed with a focus on in situ and operando molecular insights.

Cited by 92 publications

References 137 publications

Illuminating the Intrinsic Effect of Water Co-feeding on Methane Dehydroaromatization: A Comprehensive Study

Illuminating the Intrinsic Effect of Water Co-feeding on Methane Dehydroaromatization: A Comprehensive Study

Introducing Methane Activation

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na2WO4/SiO2 Catalysts

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New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na₂WO₄/SiO₂ Catalysts