Plateau potentials of the α+β palladium hydride electrode at temperatures between 25 and 195°C

Dobson, J.V.; Dagless, M. N.; Thirsk, H. R.

doi:10.1039/f19726800764

Cited by 19 publications

(17 citation statements)

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“…Previously, both palladium hydride (1,(9)(10)(11)(12)(13) and platinized (or palladized) platinum hydrogen electrodes (2-7) have been employed for this purpose. However, both electrodes suffer from a number of problems that may prevent their use in specific systems.…”

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confidence: 99%

Stabilized Ceramic Membrane Electrodes for the Measurement of pH at Elevated Temperatures

Tsuruta

Macdonald

1982

J. Electrochem. Soc.

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The use of a ceramic (ZrO2 + 17%Y~O3) membrane for the measurement of pH at elevated temperatures is described. The measurement system consists of matched membrane and external pressure-balanced reference electrodes, both of which have their internal Ag/AgC1 sensing elements at ambient temperature in order to avoid thermal degradation. The pH response of the system has been calibrated using B(OH)3 + KOH and H2SO4 + Na2SO~ test solutions whose pH values were determined at various temperatures between 25 ~ and 275~ using an in situ hydrogen electrode. The ceramic membrane has been shown to exhibit a Nernstian pH response, particularly at elevated temperatures (T > 200~ although an "acid error" was observed for weakly acidic environments.

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confidence: 99%

Stabilized Ceramic Membrane Electrodes for the Measurement of pH at Elevated Temperatures

Tsuruta

Macdonald

1982

J. Electrochem. Soc.

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“…The phase diagram for the palladium hydrogen system has been extensively studied by many workers (9)(10)(11)(12)(13)(14)(15)(16), and the average of their data is shown in Fig. 7 together with the diffusion coefficients for hydrogen in ~ -0.9 …”

Section: Resultsmentioning

confidence: 99%

“…Many metal ions and anions are stable in hydrogenated systems and hydrogen electrodes have been shown to function at elevated temperatures. However, the problems involved with these electrodes are the precise determination of hydrogen fugacity and the difficulty of application for in situ pH measurements.The potential decay of palladium-hydride electrodes has been used for the measurement of pH in high temperature aqueous systems by a number of workers (1,(9)(10)(11)(12). The work of Dobson and co-workers (9-12) on this system has indicated that palladium-hydride electrodes exhibit Nernstian responses up to 195~ However, their work was restricted to highly acidic or basic solutions, and no data were obtained for the technologically important pH range from 5 to 13.…”

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confidence: 99%

Measurement of pH and Redox Potential in Boric Acid/Lithium Hydroxide Buffer Solutions at Elevated Temperatures

Tsuruta

Macdonald

1981

J. Electrochem. Soc.

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A palladium-hydride electrode (Pd black on Pt) was used for the measurement of pH in high temperature aqueous systems (25~176 The electrode potential was calibrated against boric acid/lithium hydroxide buffer solutions, whose PHT vs. temperature profiles have been calculated (1) using known dissociation constants for the components. The plateau potential for the ~ ~-~ phase was observed up to 150~ but was not observed above 200~The potential measured above 200~ was identified to be the redox potential and to correspond to the hydrogen electrode potential in the case of a hydrogenated system. The redox potential measured in hydrogenated systems were found to exhibit linear Nernstian responses to temperatures up to 275~ but deviations of the measured potentials from equilibrium values were detected at temperatures above 200~ The deviations are most probably due to uncertainties in the thermal and isothermal liquid junction potentials associated with the external reference electrode, and to uncertainties in the thermodynamic properties of high temperature aqueous solutions.The importance of pH and redox potential measurements in high temperature aqueous systems, such as BWR and PWR (primary, secondary) nuclear systems, geothermal brines, chemical industries process waters, and for characterizing the solutions which have been used extensively in high temperature electrochemical studies, is widely recognized. A major obstacle to the measurement of pH at elevated temperatures is the lack of a reliable and generally applicable method for measuring the activity of hydrogen ion in these hostile environments. The precise pH measurements using concentration cells, which have been described by Mesmer et al. (2)(3)(4)(5) and Macdonald and co-workers (6-8), and the use of single hydrogen electrodes, require the presence of molecular hydrogen in the system. Accordingly, these techniques are applicable only to those systems that are stable to reduction by molecular hydrogen. Many metal ions and anions are stable in hydrogenated systems and hydrogen electrodes have been shown to function at elevated temperatures. However, the problems involved with these electrodes are the precise determination of hydrogen fugacity and the difficulty of application for in situ pH measurements.The potential decay of palladium-hydride electrodes has been used for the measurement of pH in high temperature aqueous systems by a number of workers (1,(9)(10)(11)(12). The work of Dobson and co-workers (9-12) on this system has indicated that palladium-hydride electrodes exhibit Nernstian responses up to 195~ However, their work was restricted to highly acidic or basic solutions, and no data were obtained for the technologically important pH range from 5 to 13. Recently, the palladium-hydride electrode has been used by Macdonald et al. (1) for the measurement of pH in various boric acid/lithium hydroxide buffer solutions ranging in pH (25~ between 5 and 13 at temperatures to 275~ Although linear potential vs. pH correlations were observed for all temperat...

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“…For example, Dobson et al [61][62][63], Macdonald and coworkers [7,64,65], and nagy and Yonco [66] explored the palladium/hydrogen system as a reference electrode, as well as a pH indicator electrode. The work by Dobson et al [61][62][63] and Macdonald © Woodhead Publishing Limited, 2012 [7,64,65] used palladium wire or palladized platinum electrodes that had been cathodically charged into the b region of the Pd-H phase diagram, where solid palladium hydrides are formed ( Fig. 11.12).…”

Section: Other Internal Reference Electrodesmentioning

confidence: 99%

Electrochemical techniques for monitoring and controlling corrosion in water-cooled nuclear reactor systems

Macdonald

2012

Nuclear Corrosion Science and Engineering

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Plateau potentials of the α+β palladium hydride electrode at temperatures between 25 and 195°C

Cited by 19 publications

References 0 publications

Stabilized Ceramic Membrane Electrodes for the Measurement of pH at Elevated Temperatures

Stabilized Ceramic Membrane Electrodes for the Measurement of pH at Elevated Temperatures

Measurement of pH and Redox Potential in Boric Acid/Lithium Hydroxide Buffer Solutions at Elevated Temperatures

Electrochemical techniques for monitoring and controlling corrosion in water-cooled nuclear reactor systems

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