Transition-Metal Catalysts for Methane Dehydroaromatization (Mo, Re, Fe): Activity, Stability, Active Sites, and Carbon Deposits

Liu, Yujie; Ćoza, Marita; Drozhzhin, Victor; Bosch, Yannis van den; Meng, Lingqian; Poll, R.; Hensen, Emiel J. M.

doi:10.1021/acscatal.2c04962

Cited by 14 publications

(15 citation statements)

References 42 publications

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“…In line with the catalytic results (Figure a), we observed that the length of the rapid weight gain stage is reduced from 186 to 111 min, by increasing the Fe content from 0.9 to 1.6 wt %. We should note that the duration of this period for impregnated Fe/ZSM-5 catalysts can be as high as 1000 min under the same reaction conditions . Therefore, we can conclude that the improved Fe dispersion leads to a faster formation of active hydrocarbon pool intermediates, significantly shortening the induction period.…”

Section: Resultsmentioning

confidence: 81%

“…We should note that the duration of this period for impregnated Fe/ZSM-5 catalysts can be as high as 1000 min under the same reaction conditions. 16 Therefore, we can conclude that the improved Fe dispersion leads to a faster formation of active hydrocarbon pool intermediates, significantly shortening the induction period. This observation correlates well with the catalytic performance of catalysts shown in Figure 4c.…”

Section: Evolution Of Surface Carbon On [Feal]zsm-5mentioning

confidence: 85%

“…The reactor effluent mixture was separated and analyzed continuously by an online GC, which has been described in detail before. 16 The presented catalytic results are averaged from three identical experiments. Methane conversion (eq 1), total converted methane along the 1000 min of the reaction (eq 2), carbon yields (eq 3), and carbon selectivity of a certain product (eq 4) were determined, based on the carbon balance (3)…”

Section: Catalyst Characterizationmentioning

confidence: 99%

“…The duration of the induction period is a reliable performance descriptor for the MDA activity of Fe-containing catalysts, in other words, Fe-containing ZSM-5 catalysts with a shorter induction period demonstrate higher catalytic activity. 16 Stability tests were performed to determine the feasibility of reaction-regeneration cycling of the [Fe,Al]ZSM-5 catalysts. We used a reaction-regeneration protocol involving reaction in a CH 4 flow of 30 mL/min at 700 °C for 180 min and a regeneration process in diluted air (10 mL/min Air +20 mL/ min He) for 60 min, either at 700 °C or 550 °C (Figure S8).…”

Section: Fe Speciation In [Feal]zsm-5mentioning

confidence: 99%

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Isomorphously Substituted [Fe,Al]ZSM-5 Catalysts for Methane Dehydroaromatization

et al. 2023

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Dehydroaromatization of methane (MDA) under non-oxidative conditions is a promising reaction for direct valorization of natural gas and biogas. Typically, Fe-modified ZSM-5 catalysts display low aromatic productivity and high coke selectivity in the MDA reaction. Herein, we show the benefit of starting from isomorphously substituted Fe-sites in [Fe,Al]ZSM-5 zeolites prepared by direct hydrothermal synthesis. Upon calcination, these samples contain predominantly isolated Fe 3+ species, either atomically dispersed within the zeolite framework or anchored at exchange sites inside zeolite channels. In terms of the integral hydrocarbon productivity, [Fe,Al]ZSM-5 catalysts outperform Fe/ZSM-5, prepared by impregnation, as well as Mo/ ZSM-5 catalysts with the same Si/Al ratio and molar metal loading. Operando X-ray absorption spectroscopy coupled with mass spectrometry (XANES-MS) demonstrates that the initial tetrahedral Fe 3+ within the zeolite framework or at exchange sites are transformed into octahedral extraframework Fe 2+ active sites during the MDA reaction and form small Fe 2 O 3 clusters during oxidative regeneration. Combining activity measurements and operando thermogravimetry shows that the duration of the induction period, related to the formation of active hydrocarbon pool intermediates, strongly depends on the Fe dispersion and loading and can be used as a suitable descriptor for the MDA activity of [Fe,Al]ZSM-5. The shorter induction period of [Fe,Al]ZSM-5 in comparison to impregnated Fe/ZSM-5 can be linked to the higher methane conversion rate over highly dispersed Fe-sites and faster formation of active hydrocarbon pool intermediates.

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Section: Resultsmentioning

confidence: 81%

Section: Evolution Of Surface Carbon On [Feal]zsm-5mentioning

confidence: 85%

Section: Catalyst Characterizationmentioning

confidence: 99%

Section: Fe Speciation In [Feal]zsm-5mentioning

confidence: 99%

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Isomorphously Substituted [Fe,Al]ZSM-5 Catalysts for Methane Dehydroaromatization

et al. 2023

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“…Multivariate curve resolution-alternating least-squares (MCR-ALS) analysis showed that the operando XANES can be best described by two components (Figure c,d). Details of MCR-ALS analysis are provided in Figures S18 and S19. , Component C1, which is similar to the XANES spectrum of the SrO reference, can be used to describe the spectrum of 0.2Sr/ZSM-5 in the absence of methanol. During methanol conversion, adsorption of water, methanol, and DME, and possibly, hydrocarbons, on Sr 2+ species leads to the appearance of a second spectral component C2, which resembles the Sr(OH) 2 ·8H 2 O reference.…”

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confidence: 99%

Role of Strontium Cations in ZSM-5 Zeolite in the Methanol-to-Hydrocarbons Reaction

Liutkova,

Drozhzhin,

Heinrichs

et al. 2023

J. Phys. Chem. Lett.

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The selectivity of the methanol-to-hydrocarbons (MTH) reaction can be tuned by modifying zeolite catalysts with alkaline earth metals, which typically increase propylene selectivity and catalyst stability. Here we employed Sr2+ as its higher atomic number in comparison to the zeolite T atoms facilitates characterization by scanning transmission electron microscopy and operando X-ray absorption spectroscopy. Sr2+ dispersed in the ZSM-5 micropores coordinates water, methanol, and dimethyl ether during the MTH reaction. Complementary characterization with nuclear magnetic resonance spectroscopy, thermogravimetric analysis combined with mass spectrometry, operando infrared spectroscopy, and X-ray diffraction points to the retention of substantially more adsorbates during the MTH reaction in comparison to Sr-free zeolites. Our findings support the notion that alkaline earth metals modify the porous reaction environment such that the olefin cycle is favored over the aromatic cycle in the MTH, explaining the increased propylene yield and lower deactivation rate.

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Hierarchical Crystalline/Amorphous Heterostructure MoNi/NiMoO_x for Electrochemical Hydrogen Evolution with Industry‐Level Activity and Stability

Shi,

Zheng,

Wang

et al. 2023

Adv Funct Materials

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The design of cheap, efficient, and durable electrocatalysts for high‐throughput H2 production is critical to give impetus to hydrogen production from fundamental to practical industrial applications. Here, a hierarchical heterostructure hydrogen evolution reaction (HER) electrocatalyst (MoNi/NiMoOx) with 0D MoNi nanoalloys nanoparticles embedded on well‐assembled 1D porous NiMoOx microrods in situ grown on 3D nickel foam (NF) is successfully constructed. The synergetic effect of different building units in the unique hierarchical structure endows the MoNi/NiMoOx composites with the highly active heterogeneous interface with low water dissociation energy (ΔGdiss = −1.2 eV) and optimized hydrogen adsorption ability (ΔGH* = −0.01 eV), fast electron/mass transport, and strong catalyst‐support binding force. As a result, optimal MoNi/NiMoOx exhibits an ampere‐level current density of 1.9 A cm−2 at an ultralow overpotential of 139 mV in 1.0 м KOH and 289 mV in 1.0 м PBS solution, respectively. Particularly, scaled‐up MoNi/NiMoOx electrodes in a 10 × 10 cm2 membrane electrode assembly (MEA) electrolyzer reach a high H2 production rate of 12.12 L h−1 (12.12 times than that of commercial NF) and exhibit ultralong stability of 1600 h, verifying its huge potential for industrial hydrogen production.

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Transition-Metal Catalysts for Methane Dehydroaromatization (Mo, Re, Fe): Activity, Stability, Active Sites, and Carbon Deposits

Cited by 14 publications

References 42 publications

Isomorphously Substituted [Fe,Al]ZSM-5 Catalysts for Methane Dehydroaromatization

Isomorphously Substituted [Fe,Al]ZSM-5 Catalysts for Methane Dehydroaromatization

Role of Strontium Cations in ZSM-5 Zeolite in the Methanol-to-Hydrocarbons Reaction

Hierarchical Crystalline/Amorphous Heterostructure MoNi/NiMoO_x for Electrochemical Hydrogen Evolution with Industry‐Level Activity and Stability

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Transition-Metal Catalysts for Methane Dehydroaromatization (Mo, Re, Fe): Activity, Stability, Active Sites, and Carbon Deposits

Cited by 14 publications

References 42 publications

Isomorphously Substituted [Fe,Al]ZSM-5 Catalysts for Methane Dehydroaromatization

Isomorphously Substituted [Fe,Al]ZSM-5 Catalysts for Methane Dehydroaromatization

Role of Strontium Cations in ZSM-5 Zeolite in the Methanol-to-Hydrocarbons Reaction

Hierarchical Crystalline/Amorphous Heterostructure MoNi/NiMoOx for Electrochemical Hydrogen Evolution with Industry‐Level Activity and Stability

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Product

Resources

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Hierarchical Crystalline/Amorphous Heterostructure MoNi/NiMoO_x for Electrochemical Hydrogen Evolution with Industry‐Level Activity and Stability