Electrical potential near hydrated surface of ordered mesoporous molecular sieves assessed by EPR of molecular pH-probes

Electrical potential near hydrated surface of ordered mesoporous molecular sieves assessed by EPR of molecular pH-probes Full article

Journal

Microporous and Mesoporous Materials
ISSN: 1387-1811 , E-ISSN: 1873-3093

Output data

Year: 2015, Volume: 203, Pages: 1-7 Pages count : 7 DOI: 10.1016/j.micromeso.2014.10.010

Tags

Double electrical layer; Zeta, Stern, Surface electrical potentials; Ordered mesoporous materials; pH-sensitive nitroxide radicals

Authors

Kovaleva Elena G. ¹ , Molochnikov Leonid S. ² , Golovkina Elena L. ² , Hartmann Martin ³ , Kirilyuk Igor A. ⁴ , Grigoriev Igor A. ⁴

Affiliations

1	nstitute of Chemical Engineering, Ural Federal University, Mira St., 19, 620002 Yekaterinburg, Russia
2	Department of Inorganic and General Chemistry, Ural State Forest Engineering University, Siberian Highway, 37, 620100 Yekaterinburg, Russia
3	Erlangen Catalysis Resource Center (ECRC), Friedrich-Alexander Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany
4	Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Akad. Lavrent’ev Av., 9, 630090 Novosibirsk, Russia

Some of the most important parameters of mesoporous materials are Stem potential of double electrical layer (DEL) and surface charge because of the pivotal role they play in the adsorption of charged molecular species. There are not any conventional and easy-to-perform techniques used to measure Stern potential in porous systems. The purpose of this work is to measure Stern potential in a specific case, i.e., practically cylindrical nanosized hydrated channels of the mesoporous molecular sieves (MMS) MCM-41 and SBA-15 with channel diameters ranging from 2.3 to 8.1 nm using pH-sensitive nitroxide radicals (NR). A technique for direct measurement of the near-surface (Stern) potential using pH-sensitive NR was developed. Negative and positive values of Stern potential for the positively and negatively charged surface of MMS channels were found. The ranges of pH of external solution for the near-zero charge, boost-charging of the channel surface and for dissociation of functional groups in the MMS studied were found. (C) 2014 Elsevier Inc. All rights reserved.

Kovaleva E.G. , Molochnikov L.S. , Golovkina E.L. , Hartmann M. , Kirilyuk I.A. , Grigoriev I.A.
Electrical potential near hydrated surface of ordered mesoporous molecular sieves assessed by EPR of molecular pH-probes
Microporous and Mesoporous Materials. 2015. V.203. P.1-7. DOI: 10.1016/j.micromeso.2014.10.010 WOS Scopus

Published print:

Feb 1, 2015

Web of science	WOS:000347593000001
Scopus	2-s2.0-84926187477
OpenAlex	W2070201066