Structural and surface considerations on Mo/ZSM-5 systems for methane dehydroaromatization reaction

López-Martín, Ángeles; Caballero, A.; Colón, G.

doi:10.1016/j.mcat.2020.110787

Cited by 15 publications

(19 citation statements)

References 23 publications

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“…This is a typical band of MoO 3 . 19 This result can confirm that the main Mo species should be MoO 3 , in accordance with the result of XRD measurements. The bands at around 350 and 470 nm can be assigned to Cr 6+ , for all Mo and Cr co-doped catalysts, which can confirm that the desired Cr 6+ spices were still present even after Mo-loading for Cr-loaded ZSM-5 samples.…”

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confidence: 88%

Improved methane dehydroaromatization reaction over Mo and Cr co-doped ZSM-5 catalyst

et al. 2023

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supporting

confidence: 88%

Improved methane dehydroaromatization reaction over Mo and Cr co-doped ZSM-5 catalyst

et al. 2023

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“…[ 9,10 ] Moreover, a drop in pore volume and size was also realized from the BET measurement, which further demonstrated the migration of Mo‐oxo species within the pore channels and their possible anchoring with Bronsted acid sites. [ 38,52,54 ] Conversely, the CZO‐promoted Mo/HZSM‐5 catalyst showed Types I and III isotherms with a small hysteresis loop at the relative pressure P/P o = 0.45–1.0 suggesting the existence of mesoporosity in the sample due to intercrystalline space and CZO mixing. Additionally, surface area and pore volume were showing a considerable decrement upon loading of CZO in the catalyst, which might be on account of the penetration of some amount of CZO oxides inside the zeolite pores, which causes the reduction in pore volume.…”

Section: Resultsmentioning

confidence: 99%

Catalytic conversion of methane into benzene over ceria–zirconia‐promoted molybdenum‐supported zeolite for methane dehydroaromatization

Mishra

Modak

Pant

et al. 2023

Applied Organom Chemis

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The promotional effect of mixed ceria–zirconia oxides (CZO) over the Mo/HZSM‐5 catalyst for methane dehydroaromatization (MDA) reaction was studied. The surface and structural properties of the synthesized catalyst were thoroughly exemplified using various microscopic and spectroscopic tools, and the correlation between catalytic properties and its performance for MDA reaction is discussed. The impregnation of CZO solid solution on Mo/HZSM‐5 was monitored to give an excellent catalytic performance and improved benzene production rate (4.5 μmol/gcat.s) related to the conventionally prepared Mo/HZSM‐5 (3.1 μmol/gcat.s) catalyst. In addition, a significant reduction in coke formation was examined in the CZO‐modified Mo/HZSM‐5 catalyst. The prevailing comprehension for higher catalytic activity could be because of the redox properties of CZO‐deposited Mo/HZSM‐5, which acts as a selective oxygen supplier and performs hydrogen combustion during the reaction, which is indirectly probed by residual gas analysis‐mass spectroscopy, oxygen‐temperature programmed desorption, and hydrogen‐temperature programmed reduction analysis. The selective hydrogen combustion prevents the over‐oxidation of aromatic species formed during the reaction, whereas the generated steam helps in reducing the coke content deposition in the MDA reaction. Thus, the advantage of CZO‐incorporated Mo/HZSM‐5 is manifested as it promotes the reaction equilibrium to shift towards the formation of benzene which is favourable for MDA reaction.

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“…The resu XPS and TEM analysis clearly confirm that the higher degree of carburization fo HMCM-49 can be ascribed to the higher concentration of MoOx species anchor The Mo 3d region XPS spectra of the C-Mo-HMCM-49 and N-Mo-HMCM-49 catalysts before and after reaction under CH 4 flow at 700 • C for 30 and 430 min are shown in Figure 8. Molybdenum carbide (Mo 2 C) dispersed in zeolite channels is the active site of C-H bond activation, and is formed during the induction stage of the MDA reaction process [5,43]. It can be observed that the Mo 3d binding energies at 236.6 and 233.4 eV can respectively be assigned to the Mo 6+ (3d 3/2 ) and Mo 6+ (3d 5/2 ) molybdenum oxide species for fresh catalysts, whereas the binding energy at 228.9 eV can be attributed to the molybdenum carbide species (Mo 2 C) formed for the catalysts after the reaction under CH 4 flow at 700 • C for 30 and 430 min.…”

Section: Samplesmentioning

confidence: 99%

MoO3 Nanobelt-Modified HMCM-49 Zeolite with Enhanced Dispersion of Mo Species and Catalytic Performance for Methane Dehydro-Aromatization

et al. 2022

Molecules

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The methane dehydro-aromatization reaction (MDA) is a promising methane valorization process due to the conversion of methane to value-added aromatics (benzene, toluene and naphthalene). However, one of the major disadvantages of utilizing zeolite in MDA is that the catalyst is rapidly inactivated due to coke formation, which eventually causes the activity and aromatic selectivity to decrease. Consequently, the process is not conducive to large-scale industrial applications. The reasonable control of Mo site distribution on the zeolite surface is the key factor for partially inhibiting the coking of the catalyst and improving stability. Here, MoO3 nanobelts can be used for alternative Mo precursors to prepare MDA catalysts. Catalysts modified with MoO3 nanobelts present higher activity (13.4%) and benzene yield (9.2%) than those catalysts loaded with commercial MoO3.

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Structural and surface considerations on Mo/ZSM-5 systems for methane dehydroaromatization reaction

Cited by 15 publications

References 23 publications

Improved methane dehydroaromatization reaction over Mo and Cr co-doped ZSM-5 catalyst

Improved methane dehydroaromatization reaction over Mo and Cr co-doped ZSM-5 catalyst

Catalytic conversion of methane into benzene over ceria–zirconia‐promoted molybdenum‐supported zeolite for methane dehydroaromatization

MoO3 Nanobelt-Modified HMCM-49 Zeolite with Enhanced Dispersion of Mo Species and Catalytic Performance for Methane Dehydro-Aromatization

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