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X-ray photoelectron spectroscopic and electrochemical impedance spectroscopic analysis of RuO2-Ta2O5 thick film pH sensors

Manjakkal, Libu; Cvejin, Katarina; Kulawik, Jan; Zaraska, Krzysztof; Socha, Robert P.; Szwagierczak, Dorota

Authors

Katarina Cvejin

Jan Kulawik

Krzysztof Zaraska

Robert P. Socha

Dorota Szwagierczak



Abstract

The paper reports on investigation of the pH sensing mechanism of thick film RuO2-Ta2O5 sensors by using X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Interdigitated conductimetric pH sensors were screen printed on alumina substrates. The microstructure and elemental composition of the films were examined by scanning electron microscopy and energy dispersive spectroscopy. The XPS studies revealed the presence of Ru ions at different oxidation states and the surface hydroxylation of the sensing layer increasing with increasing pH. The EIS analysis carried out in the frequency range 10 Hz–2 MHz showed that the electrical parameters of the sensitive electrodes in the low frequency range were distinctly dependent on pH. The charge transfer and ionic exchange occurring at metal oxide-solution interface were indicated as processes responsible for the sensing mechanism of thick film RuO2-Ta2O5 pH sensors.

Journal Article Type Article
Acceptance Date May 11, 2016
Online Publication Date Jun 7, 2016
Publication Date 2016-08
Deposit Date Jul 20, 2022
Journal Analytica Chimica Acta
Print ISSN 0003-2670
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 931
Pages 47-56
DOI https://doi.org/10.1016/j.aca.2016.05.012
Keywords Spectroscopy; Environmental Chemistry; Biochemistry; Analytical Chemistry
Public URL http://researchrepository.napier.ac.uk/Output/2890985