Rotational and Translational Motion of Benzene in ZIF-8 Studied by H-2 NMR: Estimation of Microscopic Self-Diffusivity and Its Comparison with Macroscopic Measurements | Sciact - CRIS-система Института катализа

Rotational and Translational Motion of Benzene in ZIF-8 Studied by H-2 NMR: Estimation of Microscopic Self-Diffusivity and Its Comparison with Macroscopic Measurements Научная публикация

Журнал

The Journal of Physical Chemistry C
ISSN: 1932-7447 , E-ISSN: 1932-7455

Вых. Данные

Год: 2014, Том: 118, Номер: 24, Страницы: 12873-12879 Страниц : 7 DOI: 10.1021/jp5026834

Ключевые слова

Crystalline materials; Diffusion in liquids; Microporous materials; Molecular dynamics

Авторы

Kolokolov Daniil I. ^1,2 , Diestel Lisa ³ , Caro Juergen ³ , Freude Dieter ⁴ , Stepanov Alexander G. ^1,2

Организации

1	Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Prospekt Akademika Lavrentieva 5, Novosibirsk 630090, Russia
2	Faculty of Natural Sciences, Department of Physical Chemistry, Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russia
3	Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstrasse 3A, 30167 Hannover, Germany
4	Universitat Leipzig, Fakultat fur Physik und Geowissenschaften, Linnestrasse 5, 04103 Leipzig, Germany

Информация о финансировании (2)

1	Российский фонд фундаментальных исследований	14-03-91333
2	German Research Foundation	1362

In relation to unique properties of metal–organic framework (MOF) ZIF-8 to adsorb and separate hydrocarbons with kinetic diameters notably larger than the entrance windows of the porous system of this microporous material, the molecular dynamics of benzene adsorbed on ZIF-8 has been characterized and quantified with 2H nuclear magnetic resonance. We have established that within the ZIF-8 cage the benzene molecule undergoes fast rotations, hovering in the symmetric potential of the spherical cage and relatively slow isotropic reorientations by collisions with the walls. Benzene performs also translational jump diffusion between neighboring cages characterized by an activation barrier ED = 38 kJ mol–1 and a pre-exponential factor τD0 = 4 × 10–10 s. This microscopic measurement of benzene mobility allows us to estimate the self-diffusion coefficient for benzene in ZIF-8 (D0self ≈ 4 × 10–16 m2 s–1 at T = 323 K). Macroscopic measurements of diffusivities derived from membrane permeation studies (3.5 × 10–15 m2 s–1 at T = 298 K for fractional occupancy Θ ≈ 0.99) and sorption uptake (Di,MS ≈ 10–20 m2 s–1 at 323 K) are several orders of magnitude larger or smaller than the microscopic self-diffusion coefficient D0self, which was derived from relaxation time analysis. This experimental finding is attributed to the limits of macroscopic measurements.

Kolokolov D.I. , Diestel L. , Caro J. , Freude D. , Stepanov A.G.
Rotational and Translational Motion of Benzene in ZIF-8 Studied by H-2 NMR: Estimation of Microscopic Self-Diffusivity and Its Comparison with Macroscopic Measurements
The Journal of Physical Chemistry C. 2014. V.118. N24. P.12873-12879. DOI: 10.1021/jp5026834 WOS Scopus РИНЦ CAPlusCA OpenAlex

Поступила в редакцию:	18 мар. 2014 г.
Принята к публикации:	15 мая 2014 г.
Опубликована online:	11 июн. 2014 г.
Опубликована в печати:	19 июн. 2014 г.

Web of science:	WOS:000337783900033
Scopus:	2-s2.0-84903184959
РИНЦ:	24061605
Chemical Abstracts:	2014:880050
Chemical Abstracts (print):	161:77929
OpenAlex:	W2329225027

БД	Цитирований
Web of science	37
Scopus	37
РИНЦ	37
OpenAlex	44