Synergy between vanadium and molybdenum in bimetallic ZSM-5 supported catalysts for ethylene ammoxidation

Rhimi, Baker; Mhamdi, Mourad; Kalevaru, V. Narayana; Martin, Andreas

doi:10.1039/c6ra09736g

Cited by 31 publications

(27 citation statements)

References 61 publications

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“…Indirect methods probing acidity: H/D exchange, [43,75,80] 1 H NMR, [94,121] Al NMR, [108][109][110] NH 3 -TPD [52,77,111,112] and probing adsorbed molecules by FTIR, [40,113] Acid sites partly blocked by coke, which forms together with the transformation of Mo to its active phase Dispersion Location Nuclearity UV-Vis, [67,68,97] UV-Raman [79,99,108] Difficult to get information on reduced/carbidic structures 13 C NMR Signal rather broad Probing adsorbed molecules by FTIR [87,88] Only indirect information from full width at half maximum and together with theoretical calculation. Access can be blocked by coke H 2 -TPR [115] Indirect method, nuclearity has to be inferred from reducibility Stoichiometry 13 C NMR, DNP 13 C NMR Signal rather broad Information about removed oxygen: Temperature programmed reaction using CH 4 [114] There will not only be carbidic carbon deposition but also carbonaceous carbon Information about deposited carbon: Temperature programmed reaction using CO Geometry XANES [31,40,98] Bulk technique, only an average over many structures is observed EXAFS [31,40] No long range structure for well dispersed species, only bulk Mo 2 C observed Charge XANES [30,39,70] Bulk technique, only an average over many structures is observed EPR [94,95] Only information about paramagnetic species XPS [7,100] Surface sensitive, only information about the surface is obtained Probing adsorbed...…”

Section: Type Of Information Spectroscopic Techniques Difficultiesmentioning

confidence: 99%

“…This could be achieved by probing how many BAS are replaced by Mo, probing acidity through H/D exchange, [43,75,80] 1 H NMR, [121] Al NMR, [108,109] NH 3 -TPD [52,77,111,112] or probing adsorbed molecules by FTIR. [40,113] An alternative reaction mechanism proposed proceeds via methyl radicals. [36] While their role for MDA over zeolite catalysts is mostly speculative, they have been shown to play a role above 1000 8C when a Fe@SiO 2 catalyst with a very low surface area was used.…”

Section: Topology Brønsted Acidity and The Aromatization Reactionsmentioning

confidence: 99%

“…A couple of indirect methods are available to characterize the dispersion of the metal, probing how many acid sites are replaced by a metal. This was effectively achieved by H/D exchange,,, 1 H NMR,, 27 Al NMR, NH 3 ‐TPD,,, and probing adsorbed molecules by FTIR,. CH 4 ‐TPR and H 2 ‐TPR were also used to study the ease of reduction of the Mo species present on the zeolite.…”

Section: Understanding the Structure Of The Metal Sitementioning

confidence: 99%

“…On the as‐synthesized catalyst, the interaction of the metal with the support can be probed indirectly by measuring acidity. This can be done using H/D exchange,,, 1 H NMR, Al NMR,, NH 3 ‐TPD,,, and probing adsorbed molecules by FTIR,, but this is not possible when coke is also responsible for a loss in acidity. One cannot distinguish between a loss of acidity due to carbonaceous deposits and due to a metal replacing the acidic proton.…”

Section: Understanding the Structure Of The Metal Sitementioning

confidence: 99%

“…Indirect methods probing acidity: H/D exchange,,, 1 H NMR,, Al NMR, NH 3 ‐TPD,,, and probing adsorbed molecules by FTIR,,…”

Section: Understanding the Structure Of The Metal Sitementioning

confidence: 99%

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Progress in Developing a Structure‐Activity Relationship for the Direct Aromatization of Methane

et al. 2018

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To secure future supply of aromatics, methane is a commercially interesting alternative feedstock. Direct conversion of methane into aromatics combines the challenge of activating one of the strongest C−H bonds in all hydrocarbons with the selective aromatization over zeolites. To address these challenges, smart catalyst and process design are a must. And for that, understanding the most important factors leading to successful methane C−H bond activation and selective aromatization is needed. In this review, we summarize mechanistic insight that has been gained so far not only for this reaction, but also for other similar processes involving aromatization reactions over zeolites. With that, we highlight what can be learnt from similar processes. In addition, we provide an overview of characterization tools and strategies, which are useful to gain structural information about this particular metal‐zeolite system at reaction conditions. Here we also aim to inspire future characterization work, by giving an outlook on characterization strategies that have not yet been applied for the methane dehydroaromatization catalyst, but are promising for this system.

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Section: Type Of Information Spectroscopic Techniques Difficultiesmentioning

confidence: 99%

Section: Topology Brønsted Acidity and The Aromatization Reactionsmentioning

confidence: 99%

Section: Understanding the Structure Of The Metal Sitementioning

confidence: 99%

Section: Understanding the Structure Of The Metal Sitementioning

confidence: 99%

“…Indirect methods probing acidity: H/D exchange,,, 1 H NMR,, Al NMR, NH 3 ‐TPD,,, and probing adsorbed molecules by FTIR,,…”

Section: Understanding the Structure Of The Metal Sitementioning

confidence: 99%

See 3 more Smart Citations

Progress in Developing a Structure‐Activity Relationship for the Direct Aromatization of Methane

et al. 2018

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A Novel Method of 3D Printing High‐Loaded Oxide/H‐ZSM‐5 Catalyst Monoliths for Carbon Dioxide Reduction in Tandem with Propane Dehydrogenation

Lawson

Farsad

Adebayo

et al. 2020

Advanced Sustainable Systems

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Oxidative propane dehydrogenation using CO2 (CO2‐ODHP) is a potential alternative for propylene synthesis. In this study, bifunctional catalysts (V2O5, ZrO2, Cr2O3, and Ga2O3 doped H‐ZSM‐5) are synthesized through additive manufacturing for CO2‐ODHP. Characterization and correlation between the various characterizations and the catalytic results indicates that the direct 3D printing of metal oxides alongside H‐ZSM‐5 can considerably modify the surface properties and bulk oxide phase dispersion, thus leading to enhanced metal oxide reducibility and exceptional CO2‐ODHP performance. Among the metal monoliths, the mixed oxide sample with 5 wt% Cr, 10 wt% V, 10 wt% Zr, 10 wt% Ga and 65 wt% H‐ZSM‐5 displays the best activity, achieving ≈40% propane conversion, 95% propylene selectivity, and zero benzene/toluene/xylene production. Upon eliminating CO2, the catalyst monoliths all retain their long‐term stability; however, the propane conversions decrease by ≈3% and the propylene selectivities decreased by 5–15%. Nevertheless, all five samples examined here demonstrate exceptional catalytic activities and prolonged stabilities, which are attributed to the even distribution of surface acid sites produced by direct printing of the oxide and zeolite components. Overall, this study presents a novel way of manufacturing bifunctional structured catalysts that exhibit exceptional ODHP performance.

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Cr‐ and Ga‐Modified ZSM‐5 Catalyst for the Production of Renewable BTX from Bioethanol

Saini,

Oluokun,

Sharma

et al. 2024

ChemPlusChem

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Light aromatics (benzene, toluene, and xylene, collectively known as BTX) are essential commodity chemicals in the petrochemical industry. The present study examines the aromatization of bioethanol with Cr‐ and Ga‐modified ZSM‐5. Both Cr and Ga were incorporated by the ion‐exchange method. Cr‐modified ZSM‐5 outperforms the Ga‐modified ZSM‐5 and H‐ZSM‐5 catalysts. Cr‐H‐ZSM‐5 almost doubled the carbon yield of aromatics compared to H‐ZSM‐5 at an optimum reaction temperature of 450 °C. Cr‐H‐ZSM‐5 produced aromatics with a yield of ~40 %. The effect of dilution in feed on BTX production is also studied. Cr‐H‐ZSM‐5 was found to be more active than H‐ZSM‐5. Complete ethanol conversion was obtained with both pure and dilute bioethanol. The Bronsted‐Lewis acid (BLA) pair formed after metal incorporation is responsible for dehydrogenation followed by aromatization, leading to increased aromatic production.

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Synergy between vanadium and molybdenum in bimetallic ZSM-5 supported catalysts for ethylene ammoxidation

Abstract: Ammoxidation of ethylene to acetonitrile was studied on V/ZSM-5, Mo/ZSM-5 and V–Mo/ZSM-5 catalysts prepared by a solid-state ion exchange method.

Cited by 31 publications

References 61 publications

Progress in Developing a Structure‐Activity Relationship for the Direct Aromatization of Methane

Progress in Developing a Structure‐Activity Relationship for the Direct Aromatization of Methane

A Novel Method of 3D Printing High‐Loaded Oxide/H‐ZSM‐5 Catalyst Monoliths for Carbon Dioxide Reduction in Tandem with Propane Dehydrogenation

Cr‐ and Ga‐Modified ZSM‐5 Catalyst for the Production of Renewable BTX from Bioethanol

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