HCl Adsorption on Copper-Modified ZSM-5: FTIR and DFT Study

Mosallanejad, Sara; Dlugogorski, Bogdan Z.; Kennedy, Eric M.; Stockenhuber, Michael

doi:10.1021/jp3122243

Cited by 10 publications

(16 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, a strong absorption band that was centered at 2788 cm −1 is associated with HCl molecules interacting with the siliceous framework. The reduction of the silanol band intensity and the following formation of a broad absorption at 2510 cm −1 have also been reported by Mosallanejad et al for the H-bonding interaction of CuZSM-5 with HCl at room temperature [27]. …”

Section: Resultssupporting

confidence: 70%

“…These authors underlined that weak protonic acid, such as H 2 S, while inducing an increase in silanol acidity, are not able to provoke the protonation of dimethylpyridine [29,30]. In our very demanding reaction conditions, Bronsted acidity could be due to a fraction of molecularly adsorbed HCl, although the analysis of the high frequency region of the spectra does not clearly reveal such features, as discussed above [25,26,27]. On the other side, HCl can interact with the siliceous framework and we cannot rule out the breaking of some Si–O–Si bond in the mesoporous support, leading to the formation of acidic groups that are able to protonate pyridine.…”

Section: Resultsmentioning

confidence: 89%

See 1 more Smart Citation

Surface Characterization of Mesoporous CoOx/SBA-15 Catalyst upon 1,2-Dichloropropane Oxidation

et al. 2018

View full text Add to dashboard Cite

The active combustion catalyst that is based on 30 wt % cobalt oxide on mesoporous SBA-15 has been tested in 1,2-dichloropropane oxidation and is characterized by means of FT-IR (Fourier transform infrared spectroscopy) and ammonia-TPD (temperature-programmed desorption). In this work, we report the spectroscopic evidence for the role of surface acidity in chloroalkane conversion. Both Lewis acidity and weakly acidic silanol groups from SBA support are involved in the adsorption and initial conversion steps. Moreover, total oxidation reaction results in the formation of new Bronsted acidic sites, which are likely associated with the generation of HCl at high temperature and its adsorption at the catalyst surface. Highly dispersed Co oxide on the mesoporous support and Co-chloride or oxychloride particles, together with the presence of several families of acidic sites originated from the conditioning effect of reaction products may explain the good activity of this catalyst in the oxidation of Chlorinated Volatile Organic Compounds.

show abstract

Section: Resultssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 89%

Surface Characterization of Mesoporous CoOx/SBA-15 Catalyst upon 1,2-Dichloropropane Oxidation

et al. 2018

View full text Add to dashboard Cite

show abstract

“…In addition, an increased intensity of the bands at ca. 2880 and 2475 cm –1 can be ascribed to the strong hydrogen-bonded adduct, −OH···XH, between the Brønsted hydroxyls (Si-(OH)-Al) B and HX leading to proton solvation. ,, Ozin et al, who studied HCl adsorption on the HY zeolite, ascribed the higher-frequency band to red-shifted O–H vibrations and the lower frequency band to red-shifted XH vibrations in the −OH···XH adduct. In their study of HCl adsorption on the SAPO-34 zeotype, Olsbye et al ascribed both bands to the OH vibration in (Si-(OH)-Al) B that is modulated by Fermi resonance effects due to strong hydrogen bonding.…”

Section: Resultsmentioning

confidence: 99%

Aluminum Redistribution in ZSM-5 Zeolite upon Interaction with Gaseous Halogens and Hydrogen Halides and Implications in Catalysis

Paunović¹,

Mitchell²,

Verel³

et al. 2019

J. Phys. Chem. C

View full text Add to dashboard Cite

The impact of halogens (Cl2 and Br2) and hydrogen halides (HCl and HBr) on the structural stability of zeolite catalysts constitutes an important yet poorly understood aspect of their performance in methane halogenation and halomethane coupling, which are pivotal steps in the halogen-mediated upgrading of natural gas. By studying the interaction of the ZSM-5 zeolite (Si/Al = 43) as a representative system with halogens and hydrogen halides in the temperature range of halogenation and coupling reactions (573–823 K) using XRD, N2 sorption, electron microscopy, and Raman, NMR, and ex situ and in situ FTIR spectroscopy, we showed that these compounds lead to dealumination of the framework and aluminum coordination with halogens without altering the crystalline structure. Hydrogen halides lead to more extensive dealumination than molecular halogens and especially HCl over HBr. Although oxidative regeneration restores the tetrahedral aluminum sites in the case of Cl2, Br2, and HBr treatments, the realumination of HCl-treated samples is limited, particularly following exposure at temperatures greater than 673 K. This is rationalized by stronger Al–Cl compared to Al–Br bonds that promote halogenation and hamper realumination. The regeneration of the HBr-treated zeolite leads to Br2 evolution, enabling ZSM-5 to function as an HBr oxidation catalyst.

show abstract

“…The sample powders were transformed into thin, self-supporting wafers, and transferred into an in situ cell as described in a previous manuscript. 108 Before the adsorption measurements at 30 °C, samples were activated for 30 min at 450 °C under vacuum (vacuum-treated), followed by 30 min in oxygen (oxygen-treated). Subsequent to these treatment processes, NO absorption spectra were obtained over the pressure range of 0.1 μbar to 10 mbar.…”

Section: Methodsmentioning

confidence: 99%

On the Chemistry of Iron Oxide Supported on γ-Alumina and Silica Catalysts

et al. 2018

Self Cite

View full text Add to dashboard Cite

Catalysts of iron oxide on γ-alumina and silica which were prepared by an incipient wetness impregnation technique have been investigated in an effort to understand how the surface chemical properties are influenced by the nature of the supports. Surprisingly, this is the first study to compare in depth the influence of the supports on physicochemical parameters such as acidity, site nuclearity, and reducibility. In this study, surface characterisation techniques including N 2 physisorption at −196 °C, ammonia temperature-programmed desorption, inductively coupled plasma optical emission spectrometry, temperature-programmed reduction with hydrogen, CO-chemisorption, scanning electron microscopy, transmission electron microscopy, and NO adsorption by in situ Fourier transform infrared spectroscopy have been performed to understand the different surface reactions occurring over the two different supports. The aim of this study is to ascertain the primary differences between these two catalysts using several catalyst characterization techniques and correlate their chemical and structural differences to their catalytic activity in the conversion of 2-chlorophenol. The results disclose a higher density of acid sites, a smaller particle size of iron oxide, stabilization of Fe(II) aluminate after reduction on the alumina surface, and finally, the formation of isolated iron cations on the surface of alumina which are notably absent on the silica-supported catalyst.

show abstract

HCl Adsorption on Copper-Modified ZSM-5: FTIR and DFT Study

Cited by 10 publications

References 64 publications

Surface Characterization of Mesoporous CoOx/SBA-15 Catalyst upon 1,2-Dichloropropane Oxidation

Surface Characterization of Mesoporous CoOx/SBA-15 Catalyst upon 1,2-Dichloropropane Oxidation

Aluminum Redistribution in ZSM-5 Zeolite upon Interaction with Gaseous Halogens and Hydrogen Halides and Implications in Catalysis

On the Chemistry of Iron Oxide Supported on γ-Alumina and Silica Catalysts

Contact Info

Product

Resources

About