Toward Reliable Reference Electrode Calibration In Alkaline Solution

Abstract

Figure 1. a) A chart showing the distribution of different reference electrode calibration processes from 2014 to 2023 (Web of science). b) The range of calibration values for Hg/Hg₂Cl₂, Ag/AgCl and Hg/HgO reference electrodes in 0.1 and 1 M KOH solution obtained from the literature. The values represent the total range of calibration values observed for the same reference electrode in the same measuring solution. The experimental calibration values and the corresponding literature are tabulated in Tables S1–S3. Figure 2. a) The change in measured potential of a 1 M KOH solution with time in the open air. The potentials were measured with a Hg/HgO electrode containing 1 M NaOH solution against a Gaskatel Hydroflex RHE electrode. b) Calibration potential of Hg/HgO reference electrode (1 M NaOH internal solution) measured against Pt/H₂ electrode under different H₂ flow. All measurements were conducted with stirring except the black line. The measurements for the blue and black lines were performed under the same H₂ flow. c) Distribution of experimental calibration values for Hg/Hg₂Cl₂, Ag/AgCl and Hg/HgO reference electrodes in 1 M KOH and 0.1 M KOH solution. The literature calibration values and their corresponding references were tabulated in Tables S1–S3. Figure 3. Comparison of pH values obtained from different measurements and their corresponding error in potential for KOH solution. Figure 4. a) Comparison of calibration potential of a Hg/HgO reference electrode (1 M NaOH internal solution) obtained from the equation-based method and experiment-based method for KOH solution. b) Comparison of the calibration potential of a modified, liquid junction free Hg/HgO reference electrode obtained from the equation-based method and experiment-based method for KOH solution. The standard deviations in experiment-based measurements were determined from four independent measurements. The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsenergylett.5c01269. Materials and methods, descriptive notes, tables (calibration potentials, KOH molality, hydroxide ion activity coefficient and water activity, potentials), and figures (experimental setup, change in measured potential, ²⁹Si NMR spectra, pH values, potentials) (PDF) Toward Reliable Reference Electrode Calibration In Alkaline Solution 1 views 0 shares 0 downloads Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html. M.D. headed the project. P.W.M. and M.D. designed the experiments. K.D. performed all the experiments. K.D and J.N.H. wrote the manuscript with input from all the authors. All authors approved the final version of the manuscript. This project is funded by the Deutsche Forschungsgemeinschaft (Germany’s Excellence Strategy – EXC 2008/1-390540038 – UniSysCat). J.N.H and P.W.M. acknowledge support from the German Federal Ministry of Education and Research in the framework of the project “Catlab” (03EW0015A/B). This article references 40 other publications. This article has not yet been cited by other publications.