A small angle neutron scattering and electrochemical impedance spectroscopy study of the nanostructure of the iron chalcogenide glass ion-selective electrode

Bobby Pejcic; Roland De Marco; Craig E Buckley; Clinton F Maitland; Robert Knott

doi:10.1016/j.talanta.2003.11.025

A small angle neutron scattering and electrochemical impedance spectroscopy study of the nanostructure of the iron chalcogenide glass ion-selective electrode

Talanta. 2004 May 10;63(1):149-57. doi: 10.1016/j.talanta.2003.11.025.

Authors

Bobby Pejcic¹, Roland De Marco, Craig E Buckley, Clinton F Maitland, Robert Knott

Affiliation

¹ Department of Applied Chemistry, Curtin University of Technology, GPO Box U 1987, Perth 6845, WA, Australia.

PMID: 18969413
DOI: 10.1016/j.talanta.2003.11.025

Abstract

This paper presents a preliminary structural and interfacial study of the iron chalcogenide glass [i.e., Fe(x)(Ge(28)Sb(12)Se(60))(100-x)] ion-selective electrode (ISE) using small angle neutron scattering (SANS) and electrochemical impedance spectroscopy (EIS). SANS detected variations in the neutron scattering as a function of iron content in the chalcogenide glass. Furthermore, a change in the chalcogenide glass structure was observed at elevated iron dopant levels. Conversely, EIS was used to show that the iron chalcogenide membrane comprises various time constants, and the interfacial charge transfer reaction depends on the membrane iron content. Equivalent circuit modeling revealed that the charge transfer resistance decreases at elevated iron levels, and this may be related to the presence of iron defects in the glass. It is proposed that the iron chalcogenide membrane comprises an iron nanostructural network embedded in the amorphous matrix, and this directly influences the electrical conductivity and concomitant electrochemical reactivity of the glass.