Identification and Characterization of Surface Hydroxyl Groups by Infrared Spectroscopy

Hadjiivanov, Konstantin

doi:10.1016/b978-0-12-800127-1.00002-3

Cited by 294 publications

(292 citation statements)

References 679 publications

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“…1. All samples show three main region bands as usual [27,28]: the strong and sharp OH stretching band (νOH) at 3742 cm −1 is typically due to weakly acidic terminal silanol groups located on the external zeolite surface while the band at 3606 cm −1 is assigned to the "zeolitic" bridging hydroxyl Si-OH-Al groups on the inner surface and possessing a strong Brønsted acidity [29,30]. The presence of one or more bands in the region near 3660 cm −1 corresponds to OH groups on extraframework aluminium species, to which also a very weak component at 3770 cm −1 is associated.…”

Section: Ir Study Of the Surface Hydroxyl Groupsmentioning

confidence: 99%

Tuning of product selectivity in the conversion of ethanol to hydrocarbons over H-ZSM-5 based zeolite catalysts

Phung

Radikapratama

Garbarino

et al. 2015

Fuel Processing Technology

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Conversion of ethanol to hydrocarbons was investigated over H-ZSM-5 zeolite and its modification by addition of phosphorus, iron and nickel. Reaction is realized in a tubular flow reactor at atmospheric pressure. Catalyst characterization was performed by UV-vis, TG-DTA, XRD, NH3-TPD, and IR spectroscopy of the surface OH groups and of adsorbed pyridine. High P content enhances the selectivity to lower olefins, in particular ethylene, as also occurs in the case of Fe addition. Over Ni-modified zeolites, C4 and aromatic production is promoted. The role of acidity on the conversion path is briefly discussed

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Section: Ir Study Of the Surface Hydroxyl Groupsmentioning

confidence: 99%

Tuning of product selectivity in the conversion of ethanol to hydrocarbons over H-ZSM-5 based zeolite catalysts

Phung

Radikapratama

Garbarino

et al. 2015

Fuel Processing Technology

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“…broad absorption centred at 3670 cm -1 which could be assigned to another family of Al-OH groups, whose Al is at least partially connected to the BEA framework [46,50]. Isolated Al-OH groups characterized by a FT IR band at 3785 cm -1 and due to extraframework (EF) Al, were detected for sample 1, having the highest Al content.…”

mentioning

confidence: 95%

“…The characterisation of BEA catalysts is indeed broadly addressed in the literature using Py, used even with smaller size pores, such as those characteristic of MFI zeolites [50,52,53] and even if diffusional limitations can occur for the smallest pores, operation under static conditions with sufficient equilibration time should avoid this problem, as in the present case.…”

mentioning

confidence: 98%

Ethylene production via catalytic dehydration of diluted bioethanol: A step towards an integrated biorefinery

Rossetti

Compagnoni

Finocchio

et al. 2017

Applied Catalysis B: Environmental

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After a preliminary thermodynamic investigation, proper operating conditions have been selected to maximise ethylene productivity by ethanol dehydration and limit side products such as coke and higher olefins or oxygenates. We focused on the possibility to operate with a diluted bioethanol solution (ca. 50 wt%), which represents a promising and convenient raw material, obtainable by simple flash concentration of the fermentation broth. Furthermore, water addition to the ethanol dehydration reactor may help preventing catalyst coking and diethyl ether formation, although affecting the thermodynamic products distribution. A proof of concept for an ethanol dehydration process using diluted ethanol is also provided through process simulation. Catalysts based on a BEA zeolite have been compared, characterised by different acidity imparted by dealumination treatments. Ni addition in variable loading helped suppressing undesired byproducts, difficult to separate from ethylene. For instance, no trace of diethyl ether nor acetaldehyde has been observed for the Ni-loaded samples under optimised working conditions. Catalyst characterisation by FT IR allowed correlating a high selectivity to ethylene with the acid sites nature of the catalyst, whereas the presence of extraframework Lewis acidic sites induced faster coke formation. Durability was finally checked on the most active and selective catalyst evidencing stable operation for 80 h-on-stream and without evidence of coke deposition, as determined after characterisation of the spent samples. A γ-Al2O3 catalyst has been tested as benchmark under the same conditions

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“…This choice is made for simplicity and clarity, as monoclinic and tetragonal zirconias differ in, e.g., surface hydroxyl species 7,25 and acidity/basicity 7,24,30 , further demonstrated in their interactions with CO 7,25,30 and in their catalytic activity, e.g., in water-gas shift 11,12 . More information can also be found in the reviews by Dyrek et al 35 and Hadjiivanov 36 .Most of the pre-1993 works included in this paper were reviewed 20 years ago by Nawrocki et al 37 in the context of chromatography; this review is providing an update with work reported since 1993, from the perspective of catalysis.…”

Section: Introductionmentioning

confidence: 99%

Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Kouva

Honkala

Lefferts

et al. 2015

Catal. Sci. Technol.

150

138

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Identification and Characterization of Surface Hydroxyl Groups by Infrared Spectroscopy

Cited by 294 publications

References 679 publications

Tuning of product selectivity in the conversion of ethanol to hydrocarbons over H-ZSM-5 based zeolite catalysts

Tuning of product selectivity in the conversion of ethanol to hydrocarbons over H-ZSM-5 based zeolite catalysts

Ethylene production via catalytic dehydration of diluted bioethanol: A step towards an integrated biorefinery

Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

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