A Caltech Library Service

Conductivity of Mono- and Divalent Cations in the Microporous Zincosilicate VPI-9

McKeen, John C. and Davis, Mark E. (2009) Conductivity of Mono- and Divalent Cations in the Microporous Zincosilicate VPI-9. Journal of Physical Chemistry C, 113 (22). pp. 9870-9877. ISSN 1932-7447. doi:10.1021/jp902235z.

[img] PDF - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Impedance spectroscopy is used to investigate the long-range ionic conductivity of the microporous, zincosilicate VPI-9 (Si/Zn = 4.0) (International Zeolite Association framework type VNI) containing the alkali cations Li^+, Na^+, K^+, Rb^+, and Cs^+, and the alkaline earth cations Mg^(2+), Ca^(2+), and Sr^(2+). Monovalent cation-exchanged samples Li- and Na-VPI-9 lose X-ray crystallinity upon vacuum dehydration at 450 °C, whereas K-, Rb-, and Cs-VPI-9 remain crystalline and exhibit conductivities of 1.7 × 10^(−4), 3.5 × 10^(−4), and 4.9 × 10^(−4) S/cm, respectively, at 450 °C and activation energies of 0.72, 0.64, and 0.69 eV, respectively, in the temperature range 150−450 °C. Divalent cation-exchanged sample Mg-VPI-9 also loses X-ray crystallinity, but Ca- and Sr-VPI-9 remain crystalline and exhibit conductivities of 2.3 × 10^(−6) S/cm and 7.7 × 10^(−7) S/cm, respectively, at 450 °C, and activation energies of 0.88 and 0.91 eV, respectively, over the temperature range 150−450 °C. When compared to aluminosilicate zeolite X (Si/Al = 1.25) exchanged with the same cations, all crystalline M-VPI-9 materials have greater conductivities than M-X, with the exception of K-X (1.6 × 10^(−3) S/cm at 450 °C), with the greatest differences arising between the divalent exchanged materials. Dense, crystalline zincosilicate samples with the compositions K_2ZnSi_xO_(2(x+1)) (x = 2−5), Rb_2ZnSi_5O_(12), and Cs_2ZnSi_5O_(12) are also prepared and characterized for comparison with the microporous materials and exhibit much lower conductivities than their microporous counterparts at the same composition.

Item Type:Article
Related URLs:
URLURL TypeDescription
Davis, Mark E.0000-0001-8294-1477
Additional Information:Copyright © 2009 American Chemical Society. Received: March 12, 2009; Revised Manuscript Received: April 21, 2009. Publication Date (Web): May 12, 2009. J.C.M. acknowledges the Fannie and John Hertz Foundation and the National Science Graduate Research Fellowship Program for financial support. Supporting Information: A photograph of the experimental apparatus along with modulus spectra from sodium exchanged zeolite X and discussion thereof are provided in the Supporting Information. This material is available free of charge via the Internet at
Funding AgencyGrant Number
Fannie and John Hertz FoundationUNSPECIFIED
Issue or Number:22
Record Number:CaltechAUTHORS:20090901-142619577
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15533
Deposited By: George Porter
Deposited On:09 Sep 2009 18:14
Last Modified:08 Nov 2021 23:20

Repository Staff Only: item control page