Study on the sensing characteristics and hysteresis effect of the tin oxide pH electrode

Tsai, Chu-Neng; Chou, Jung-Chuan; Sun, Tai‐Ping; Hsiung, Shen‐Kan

doi:10.1016/j.snb.2004.11.050

Cited by 74 publications

(51 citation statements)

References 29 publications

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“…This result is better than many other reported data in the literatures. [15][16][17][18][19][20][21][22] Although the absolute values of the electrode potential vary to some extent, the E-pH responses of them are quite similar (51∼54 mV/pH), being close to the theoretical Nernst response (59.16 mV/pH).…”

Section: Resultsmentioning

confidence: 89%

The Effects of Cyclic Isothermal Oxidation on Ir/IrO_xpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

Huang¹,

Wan²,

Jin³

et al. 2017

J. Electrochem. Soc.

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The present work demonstrated the effects of isothermal oxidation temperature (750 • C∼870 • C) and water quenching cycle times (1∼3) on properties of IrO x pH electrodes. Property tests of the fabricated electrodes showed that electrodes developed by 800 • C isothermal heating and water quenching for 3 times (H&Q 3) had excellent near Nernst E-pH relationship, relatively faster response rate and the minimum potential drift in long-term stability test. Surface and cross-section morphologies, confocal laser scanning microscopy, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the electrodes to explore the reason for their excellent properties. Surface morphology showed that the iridium oxide film (IROF) made by H&Q 3 at 800 • C had larger surface roughness, and well-defined homogeneous dense inner layer and loose porous outer layer. Besides, it had the minimum reaction resistance in both acid and alkaline buffers, and contained more effective compositions compared to electrodes fabricated by other conditions. Thus H&Q 3 at 800 • C was suggested to obtain a better integrated pH sensing property. Furthermore, a potential compensation method with a specially designed probe structure was proposed to correct possible errors caused by the potential drift of IrO x pH electrode in long-term pH monitoring. pH, used to reflect the grade of solvents in chemical laboratory since 1909, is an important parameter in many fields such as chemical industry, bio-industry as well as some fundamental research like electrodeposition/electrolysis and corrosion process.1-3 The glass pH electrode is a mature routine tool presenting good sensitivity, excellent stability and long life time in pH sensing. However, some of its disadvantages restrict its usage in some particular applications due to the physical nature of the glass membrane.The alternative pH electrodes include ion-sensitive field-effect transistor (ISFET) pH sensors, 4,5 optical fiber pH sensors, 6,7 hydrogel film pH sensors, [8][9][10][11][12] metal/metal oxide sensors, 13-16 etc. By comparing sensitivity, Nernst response range, ion selectivity, interference of oxidation, the iridium oxide pH electrode has been demonstrated to be the most promising one among all kinds of pH sensors. [17][18][19] The reported fabrication approaches of IrO x pH electrode include electrochemical cyclic voltammetry (CV), 19-22 electrodeposition, 23-25 radio frequency (RF) magnetron sputtering deposition, 26-30 and thermal oxidation.14,31 Among which, the electrode produced by thermal oxidation exhibited excellent overall performance, including wide E-pH relationship range, fast response time and long term stability.32-36 Wang et al. developed carbonate melt oxidation to coat Ir through the oxidation of Ir wires in a carbonate melt at 870• C for 5 hours.31 Hitchman et al. produced IrO x -electrodes by direct thermal oxidation in air at 800• C. 34 Both surface films of fabricated by the above conditions showed obvious cracks...

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Section: Resultsmentioning

confidence: 89%

The Effects of Cyclic Isothermal Oxidation on Ir/IrO_xpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

Huang¹,

Wan²,

Jin³

et al. 2017

J. Electrochem. Soc.

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“…in vivo, food industry, or for clinical applications), they posses several disadvantages due to their size constraints, rigidity, and the 25 inflexibility of the glass electrode. In recent years, a wide number of pH sensors have been developed to overcome these limitations, including ion sensitive field-effect transistor (iSFET) pH sensors [1][2][3][4] , optical pH sensors based on pH responsive dyes [5][6][7][8] , hydrogel film pH sensors 9,10 , and solid-state metal oxides pH sensors [11][12][13] . 30 In particular, optical pH sensors present several advantages over the traditional pH electrodes as such their low costs, immunity from electromagnetic field, absence of electric contacts, possibility of reference electrode removal and a high degree of miniaturisation 14 .…”

mentioning

confidence: 99%

Dynamic pH mapping in microfluidic devices by integrating adaptive coatings based on polyaniline with colorimetric imaging techniques

et al. 2013

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In this paper we present a microfluidic device that has integrated pH optical sensing capabilities based on polyaniline. The optical properties of polyaniline coatings change in response to the pH of the solution that is flushed inside the microchannel offering the possibility of monitoring pH in continuous flow over a wide pH range throughout the entire channel length. This work also features an innovative detection 10 system for spatial localisation of chemical pH gradients along microfluidic channels through the use of a low cost optical device. Specifically, the use of a microfluidic channel coated with polyaniline is shown to respond colorimetrically to pH and that effect is detected by the detection system, even when pH gradients are induced within the channel. This study explores the capability of detecting this gradient by means of imaging techniques and the mapping of the camera's response to its corresponding pH after a 15 successful calibration process. The provision of an inherently responsive channel means that changes in the pH of a sample moving through the system can be detected dynamically using digital imaging along the entire channel length in real time, without the need to add reagents to the sample. This approach is generic and can be applied to other chemically responsive coatings immobilised on microchannels. Introduction 20Conventional glass-type electrodes have been widely used for pH measures for many years in both industry and academic areas. However, in terms of specific applications (e.g. in vivo, food industry, or for clinical applications), they posses several disadvantages due to their size constraints, rigidity, and the 25 inflexibility of the glass electrode. In recent years, a wide number of pH sensors have been developed to overcome these limitations, including ion sensitive field-effect transistor (iSFET) pH sensors 1-4 , optical pH sensors based on pH responsive dyes 5-8 , hydrogel film pH sensors 9, 10 , and solid-state metal oxides pH sensors 11-13 . 30 In particular, optical pH sensors present several advantages over the traditional pH electrodes as such their low costs, immunity from electromagnetic field, absence of electric contacts, possibility of reference electrode removal and a high degree of miniaturisation 14 . Optical fiber-based pH sensors have been 35 particularly popular, as the fibre allows the optical signal to be transported over long distances, which can facilitate applications in remote sensing 15 .Usually, these optical pH sensors (or optrodes) employ a dye or an indicator that requires immobilisation onto a solid support 40 material. There are several critical issues related to this approach: firstly, the dye should retain its optical properties after the immobilisation process 16 and secondly, it should not leach into the solution 17. A third issue of practical importance is their inherently narrow dynamic response range which is usually 45 around 3-4 pH-units centred on the dye´s pKa 18 .Therefore, the further improvement of such sensors focuses...

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“…Tsai et al [68] have studied the pH sensing characteristics and hysteresis effect of the R.F. sputtered tin oxide (SnO2) electrode.…”

Section: Ph Sensing Materials and Applicationsmentioning

confidence: 99%

Recent Developments in R.F. Magnetron Sputtered Thin Films for pH Sensing Applications—An Overview

2014

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pH sensors are widely used in chemical and biological applications. Metal oxides-based pH sensors have many attractive features including insolubility, stability, mechanical strength, electrocatalyst and manufacturing technology. Various metal oxide thin films prepared by radio frequency (R.F.) magnetron sputtering have attractive features, including high pH sensitivity, fast response, high resolution, good stability and reversibility as well as potential for measuring pH under conditions that are not favourable for the commonly used glass electrodes-based pH sensors. In addition, thin film pH sensors prepared by R.F. magnetron sputtering offer many advantages, such as ease of packaging, low cost through the use of standard microfabrication processes, miniaturisation, capability of measuring pH at high temperatures, ruggedness and disposability. In this paper, recent development of R.F. magnetron sputtered thin films for pH sensing applications are reviewed.

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Study on the sensing characteristics and hysteresis effect of the tin oxide pH electrode

Cited by 74 publications

References 29 publications

The Effects of Cyclic Isothermal Oxidation on Ir/IrO_xpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

The Effects of Cyclic Isothermal Oxidation on Ir/IrO_xpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

Dynamic pH mapping in microfluidic devices by integrating adaptive coatings based on polyaniline with colorimetric imaging techniques

Recent Developments in R.F. Magnetron Sputtered Thin Films for pH Sensing Applications—An Overview

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Study on the sensing characteristics and hysteresis effect of the tin oxide pH electrode

Cited by 74 publications

References 29 publications

The Effects of Cyclic Isothermal Oxidation on Ir/IrOxpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

The Effects of Cyclic Isothermal Oxidation on Ir/IrOxpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

Dynamic pH mapping in microfluidic devices by integrating adaptive coatings based on polyaniline with colorimetric imaging techniques

Recent Developments in R.F. Magnetron Sputtered Thin Films for pH Sensing Applications—An Overview

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The Effects of Cyclic Isothermal Oxidation on Ir/IrO_xpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode

The Effects of Cyclic Isothermal Oxidation on Ir/IrO_xpH Electrode and a Method to Correct the Potential Drift of Metal Oxide Electrode