Effect of Oxidization Temperatures and Aging on Performance of Carbonate Melt Oxidized Iridium Oxide pH Electrode
1
School of Civil Engineering, Qingdao University of Technology, Qingdao 266033, China
2
Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, China
3
Shenzhen Durability Center for Civil Engineering, Shenzhen University, Shenzhen 518060, China
4
Cooperative Innovation Center of Engineering Construction and Safety in Shandong Blue Economic Zone, Qingdao 266033, China
*
Author to whom correspondence should be addressed.
Sensors 2019, 19(21), 4756; https://doi.org/10.3390/s19214756
Received: 27 September 2019
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Revised: 30 October 2019
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Accepted: 31 October 2019
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Published: 1 November 2019
(This article belongs to the Special Issue Metal Oxide Based Sensors)
Iridium oxide pH electrodes employing the carbonate melt oxidation method were fabricated with oxidation temperatures of 750 °C, 800 °C and 850 °C, respectively. Scanning electron microscope (SEM) and atomic force microscope (AFM) images showed that the oxide film regularized with the increase in oxidation temperatures. The pH response, response time and long-term stability of the electrodes indicated that the electrodes made at 850 °C had the best performance. X-ray photoelectron spectra (XPS) surveys investigated the change in the electrodes’ chemical composition and element oxidation states at 850 °C, and the results showed that the relative content of Ir3+ had increased by 23.9%, and the Ir4+ and Ir6+ had decreased by 10.9% and 13%, respectively, in the surface oxide layer after one month of aging. However, the relative contents of Ir3+, Ir4+ and Ir6+ were almost constant for the inner oxide layer. Meanwhile, the XPS result also indicated that the outer oxide layer of the electrode had a higher hydration degree than the inner oxide layer.
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Keywords:
iridium oxide; pH electrode; carbonate melt oxidized; oxidation temperature; microstructure
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MDPI and ACS Style
Wang, P.; Guo, T.; Zhao, T.; Du, Z.; Jin, Z.; Dong, B.; Li, Z. Effect of Oxidization Temperatures and Aging on Performance of Carbonate Melt Oxidized Iridium Oxide pH Electrode. Sensors 2019, 19, 4756. https://doi.org/10.3390/s19214756
AMA Style
Wang P, Guo T, Zhao T, Du Z, Jin Z, Dong B, Li Z. Effect of Oxidization Temperatures and Aging on Performance of Carbonate Melt Oxidized Iridium Oxide pH Electrode. Sensors. 2019; 19(21):4756. https://doi.org/10.3390/s19214756
Chicago/Turabian StyleWang, Penggang, Tengfei Guo, Tiejun Zhao, Zhenxing Du, Zuquan Jin, Biqin Dong, and Zhe Li. 2019. "Effect of Oxidization Temperatures and Aging on Performance of Carbonate Melt Oxidized Iridium Oxide pH Electrode" Sensors 19, no. 21: 4756. https://doi.org/10.3390/s19214756
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