Promoting effect of vanadium on CF2Cl2 destructive sorption over nanocrystalline mesoporous MgO

Ilyina, Ekaterina V.; Mishakov, Ilya V.; Vedyagin, Aleksey A.; Bedilo, Alexander F.; Klabunde, Kenneth J.

doi:10.1016/j.micromeso.2013.03.034

Cited by 22 publications

(25 citation statements)

References 46 publications

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“…Without any doubt they are very active at least in these reactions. Although their structure and role in catalytic reactions are still not sufficiently understood, recent data suggest that such sites may be actually active in catalytic reactions of general interest. ,, Our recent data also suggest that weak electron-acceptor sites may account for the activity of nanocrystalline oxides in destructive sorption of harmful halogenated compounds. − …”

Section: Introductionmentioning

confidence: 87%

Characterization of Electron-Donor and Electron-Acceptor Sites on the Surface of Sulfated Alumina Using Spin Probes

et al. 2014

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Electron-donor sites on the surface of γ-Al 2 O 3 modified with different amounts of sulfates were characterized using 1,3,5-trinitrobenzene as a spin probe. The concentration of 1,3,5-trinitrobezene radical anions formed on the surface electron-donor sites was found to decrease when the sulfate concentration and the surface acidity increased. Electron-acceptor sites of different strengths were studied using the formation of radical cations after adsorption of donor aromatic molecules with different ionization potentials. Changes in the intensity of the EPR signal observed after adsorption of hexafluorobenzene, toluene, hexamethylbenzene, and anthracene on the surface of sulfated alumina samples with different sulfate concentrations were analyzed. Modification of γ-Al 2 O 3 with sulfates was found to result in the formation of strong electron-acceptor sites capable of ionizing toluene and hexamethylbenzene to their radical cations. Such sites were observed on the samples with the sulfate concentrations 4 wt % or higher. Weak electron-acceptor sites tested using anthracene were present on the surface of pure Al 2 O 3 . Their concentration was found to grow substantially when the concentration of sulfates was increased. The intensity of the EPR signal was found to depend on time after adsorption. The mechanisms of processes leading to the formation of the EPR signal attributed to electron-acceptor sites and the possible nature of such sites are discussed. Suggestions concerning the use of spin probes for characterization of electron-acceptor sites are made.

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Section: Introductionmentioning

confidence: 87%

Characterization of Electron-Donor and Electron-Acceptor Sites on the Surface of Sulfated Alumina Using Spin Probes

et al. 2014

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“…For instance, nanocrystalline mesoporous oxides with nanoparticle sizes under 10 nm oen have unusually high reactivity in many chemical reactions. This property leads to their use as efficient catalysts [1][2][3] and destructive sorbents [4][5][6][7][8][9][10] for the neutralization of various toxic compounds. However, the products resulting from their solidstate reactions are usually not nanocrystalline.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline carbon coated alumina with enhanced phase stability at high temperatures

et al. 2017

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“…This result is in a good agreement with the kinetic data reported earlier. 13 Moreover, the concentration of electron-acceptor sites on this sample is higher. Overall, the results obtained in this study clearly prove that there is a good correlation between the formation of weak electron-acceptor sites and the activity of nanocrystalline AP-MgO and AP-VO x -MgO aerogels in the reaction with CF 2 Cl 2 .…”

Section: Characterization Of Electron-donor and Electron-acceptor Sitmentioning

confidence: 73%

Study of MgO transformation into MgF2 in the presence of CF2Cl2•

Vedyagin

Bedilo

Mishakov

et al. 2017

JSCS

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Alkaline-earth metal oxide aerogels prepared by sol-gel method followed by autoclave drying are nanocrystalline mesoporous materials with high reactivity. Bulk solid-state reaction of MgO aerogels with CF 2 Cl 2 takes place after a long induction period, during which the active sites are accumulated on the surface of the nanoparticles. It was found that vanadium addition has a promoting effect on this reaction accelerating the process of the active sites formation. A method for characterization of electron-acceptor sites by electron spin resonance spectroscopy using perylene as the spin probe was developed. A good correlation was observed between the rate of the CF 2 Cl 2 destructive sorption and the concentration of weak electron-acceptor sites. Simplified models of such sites were suggested. The acid sites on the modified MgO surface were supposed to be originated from separation of the charged fragments resulting in the surface polarization. Uncompensated oxygen substitution for chlorine and/or fluorine ions leads to appearance of Lewis acid sites while HCl/HF chemisorption results in Bronsted acid sites formation.

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Promoting effect of vanadium on CF2Cl2 destructive sorption over nanocrystalline mesoporous MgO

Cited by 22 publications

References 46 publications

Characterization of Electron-Donor and Electron-Acceptor Sites on the Surface of Sulfated Alumina Using Spin Probes

Characterization of Electron-Donor and Electron-Acceptor Sites on the Surface of Sulfated Alumina Using Spin Probes

Nanocrystalline carbon coated alumina with enhanced phase stability at high temperatures

Study of MgO transformation into MgF2 in the presence of CF2Cl2•

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