Next Article in Journal
Cooperative Environment Scans Based on a Multi-Robot System
Previous Article in Journal
MEMS Sensor Technologies for Human Centred Applications in Healthcare, Physical Activities, Safety and Environmental Sensing: A Review on Research Activities in Italy
Open AccessArticle

A Solid-State Thin-Film Ag/AgCl Reference Electrode Coated with Graphene Oxide and Its Use in a pH Sensor

by Tae Yong Kim 1, Sung A Hong 1 and Sung Yang 1,2,*
1
Department of Medical System Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Korea
2
School of Mechatronics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Korea
*
Author to whom correspondence should be addressed.
Academic Editor: W. Rudolf Seitz
Sensors 2015, 15(3), 6469-6482; https://doi.org/10.3390/s150306469
Received: 12 February 2015 / Revised: 10 March 2015 / Accepted: 12 March 2015 / Published: 17 March 2015
(This article belongs to the Section Chemical Sensors)
In this study, we describe a novel solid-state thin-film Ag/AgCl reference electrode (SSRE) that was coated with a protective layer of graphene oxide (GO). This layer was prepared by drop casting a solution of GO on the Ag/AgCl thin film. The potential differences exhibited by the SSRE were less than 2 mV for 26 days. The cyclic voltammograms of the SSRE were almost similar to those of a commercial reference electrode, while the diffusion coefficient of Fe(CN)63− as calculated from the cathodic peaks of the SSRE was 6.48 × 10−6 cm2/s. The SSRE was used in conjunction with a laboratory-made working electrode to determine its suitability for practical use. The average pH sensitivity of this combined sensor was 58.5 mV/pH in the acid-to-base direction; the correlation coefficient was greater than 0.99. In addition, an integrated pH sensor that included the SSRE was packaged in a secure digital (SD) card and tested. The average sensitivity of the chip was 56.8 mV/pH, with the correlation coefficient being greater than 0.99. In addition, a pH sensing test was also performed by using a laboratory-made potentiometer, which showed a sensitivity of 55.4 mV/pH, with the correlation coefficient being greater than 0.99. View Full-Text
Keywords: Ag/AgCl; reference electrode; pH sensor; graphene oxide; iridium oxide pH working electrode; potentiometer Ag/AgCl; reference electrode; pH sensor; graphene oxide; iridium oxide pH working electrode; potentiometer
Show Figures

Figure 1

MDPI and ACS Style

Kim, T.Y.; Hong, S.A.; Yang, S. A Solid-State Thin-Film Ag/AgCl Reference Electrode Coated with Graphene Oxide and Its Use in a pH Sensor. Sensors 2015, 15, 6469-6482.

Show more citation formats Show less citations formats

Article Access Map by Country/Region

1
Only visits after 24 November 2015 are recorded.
Back to TopTop