A flexible gas flow reaction cell for in situ x-ray absorption spectroscopy studies

Kroner, Anna; Mohammed, Khaled M. H.; Gilbert, M. H.; Duller, Graham; Cahill, Leo; Leicester, Peter; Woolliscroft, R.; Shotton, Elizabeth J.

doi:10.1063/1.4952837

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…X‐ray beam dimensions at the sample position were 1×1 mm 2 , whereas the acquisition of each spectra took ∼60 s. In situ experiments were performed using a setup developed by A. B. Kroner et al . For the experiments, 40 mg of the as‐prepared catalysts (sieve fractions: 0.425–0.150 mm) were placed in a 3 mm diameter quartz capillary.…”

Section: Methodsmentioning

confidence: 99%

Implications of the Molybdenum Coordination Environment in MFI Zeolites on Methane Dehydroaromatisation Performance

et al. 2019

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The structure and activity of Mo/Silicalite‐1 (MFI, Si/Al=∞) were compared to Mo/H‐ZSM‐5 (MFI, Si/Al=15), a widely studied catalyst for methane dehydroaromatisation (MDA). The anchoring mode of Mo was evaluated by in situ X‐ray absorption spectroscopy (XAS) and density functional theory (DFT). The results showed that in Mo/Silicalite‐1, calcination leads to dispersion of MoO3 precursor into tetrahedral Mo‐oxo species in close proximity to the microporous framework. A weaker interaction of the Mo‐oxo species with the Silicalite‐1 was determined by XAS and DFT. While both catalysts are active for MDA, Mo/Silicalite‐1 undergoes rapid deactivation which was attributed to a faster sintering of Mo species leading to the accumulation of carbon deposits on the zeolite outer surface. The results shed light onto the nature of the Mo structure(s) while evidencing the importance of framework Al in stabilising active Mo species under MDA conditions.

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Section: Methodsmentioning

confidence: 99%

Implications of the Molybdenum Coordination Environment in MFI Zeolites on Methane Dehydroaromatisation Performance

et al. 2019

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“…In situ experiments were performed using a setup developed by A. B. Kroner et al [59]. Mo K-edge XAS spectra were collected under operando MDA conditions where the reaction products were detected by an online mass spectrometer (OmniStar GSD 320O1).…”

Section: Methodsmentioning

confidence: 99%

Understanding the Deactivation Phenomena of Small-Pore Mo/H-SSZ-13 during Methane Dehydroaromatisation

et al. 2020

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Small pore zeolites have shown great potential in a number of catalytic reactions. While Mo-containing medium pore zeolites have been widely studied for methane dehydroaromatisation (MDA), the use of small pore supports has drawn limited attention due to the fast deactivation of the catalyst. This work investigates the structure of the small pore Mo/H-SSZ-13 during catalyst preparation and reaction by operando X-ray absorption spectroscopy (XAS), in situ synchrotron powder diffraction (SPD), and electron microscopy; then, the results are compared with the medium pore Mo/H-ZSM-5. While SPD suggests that during catalyst preparation, part of the MoOx anchors inside the pores, Mo dispersion and subsequent ion exchange was less effective in the small pore catalyst, resulting in the formation of mesopores and Al2(MOO4)3 particles. Unlike Mo/H-ZSM-5, part of the Mo species in Mo/H-SSZ-13 undergoes full reduction to Mo0 during MDA, whereas characterisation of the spent catalyst indicates that differences also exist in the nature of the formed carbon deposits. Hence, the different Mo speciation and the low performance on small pore zeolites can be attributed to mesopores formation during calcination and the ineffective ion exchange into well dispersed Mo-oxo sites. The results open the scope for the optimisation of synthetic routes to explore the potential of small pore topologies.

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“…X-Ray beam dimensions at the sample position were 1 × 1 mm 2 . The acquisition of each spectrum took ∼120 s. In situ experiments were performed using a setup developed by Kroner et al 44 For the experiments, 40 mg of the as-prepared catalysts (sieve fractions: 0.425–0.150 mm) were placed in a 3 mm diameter quartz capillary. Prior to activation, the sample was heated using a hot gas blower under He gas flow (heating rate = 0.2 °C min −1 ).…”

Section: Experimental and Computational Detailsmentioning

confidence: 99%

Experimental and computational studies of sulfided NiMo supported on pillared clay: catalyst activation and guaiacol adsorption sites

Oemry

Adilina²,

Cahyanto

et al. 2023

Phys. Chem. Chem. Phys.

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A flexible gas flow reaction cell for in situ x-ray absorption spectroscopy studies

Cited by 3 publications

References 15 publications

Implications of the Molybdenum Coordination Environment in MFI Zeolites on Methane Dehydroaromatisation Performance

Implications of the Molybdenum Coordination Environment in MFI Zeolites on Methane Dehydroaromatisation Performance

Understanding the Deactivation Phenomena of Small-Pore Mo/H-SSZ-13 during Methane Dehydroaromatisation

Experimental and computational studies of sulfided NiMo supported on pillared clay: catalyst activation and guaiacol adsorption sites

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