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Nanostructured Pd hydride microelectrodes: in situ monitoring of pH variations in a porous medium

Nanostructured Pd hydride microelectrodes: in situ monitoring of pH variations in a porous medium
Nanostructured Pd hydride microelectrodes: in situ monitoring of pH variations in a porous medium
In this study we report the exceptional potentiometric properties of pH microprobes made with nanostructured palladium hydride microelectrodes and demonstrate their application by monitoring pH variations resulting from a reaction confined in a porous medium. Their potentiometric response was found to be reproducible and stable over several hours but primarily Nernstian over a remarkably wide pH range, including alkaline conditions up to pH 14. Continuous operation was demonstrated by reloading hydrogen at regular intervals to maintain the correct hydride composition thereby alleviating the need for calibration. These properties were validated by detecting pH transients during the carbonation of Ca(OH)2 within a fibrous mesh. Experimental pHs recorded in situ were in excellent agreement with theoretical calculations for the CO2 partial pressures considered. Results also showed that the electrodes were sufficiently sensitive to differentiate between the formation of vaterite and calcite, two polymorphs of CaCO3. These nanostructured microelectrodes are uniquely suited to the determination of pH in highly alkaline solutions, particularly those arising from interfacial reactions at solid and porous surfaces and are thus highly appropriate as pH sensing tips in scanning electrochemical microscopy.
0003-2700
5758-5765
Serrapede, Mara
a8fab211-39d3-4d28-8804-90e7578c69c5
Pesce, Giovanni Luca
e1a6d917-0788-44ab-bdd4-9dffb353be78
Ball, Richard J.
349bce36-91cb-40b4-834d-98260b42f900
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Serrapede, Mara
a8fab211-39d3-4d28-8804-90e7578c69c5
Pesce, Giovanni Luca
e1a6d917-0788-44ab-bdd4-9dffb353be78
Ball, Richard J.
349bce36-91cb-40b4-834d-98260b42f900
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e

Serrapede, Mara, Pesce, Giovanni Luca, Ball, Richard J. and Denuault, Guy (2014) Nanostructured Pd hydride microelectrodes: in situ monitoring of pH variations in a porous medium. Analytical Chemistry, 86 (12), 5758-5765. (doi:10.1021/ac500310j).

Record type: Article

Abstract

In this study we report the exceptional potentiometric properties of pH microprobes made with nanostructured palladium hydride microelectrodes and demonstrate their application by monitoring pH variations resulting from a reaction confined in a porous medium. Their potentiometric response was found to be reproducible and stable over several hours but primarily Nernstian over a remarkably wide pH range, including alkaline conditions up to pH 14. Continuous operation was demonstrated by reloading hydrogen at regular intervals to maintain the correct hydride composition thereby alleviating the need for calibration. These properties were validated by detecting pH transients during the carbonation of Ca(OH)2 within a fibrous mesh. Experimental pHs recorded in situ were in excellent agreement with theoretical calculations for the CO2 partial pressures considered. Results also showed that the electrodes were sufficiently sensitive to differentiate between the formation of vaterite and calcite, two polymorphs of CaCO3. These nanostructured microelectrodes are uniquely suited to the determination of pH in highly alkaline solutions, particularly those arising from interfacial reactions at solid and porous surfaces and are thus highly appropriate as pH sensing tips in scanning electrochemical microscopy.

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e-pub ahead of print date: 27 May 2014
Published date: 17 June 2014
Organisations: Chemistry

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Local EPrints ID: 367441
URI: http://eprints.soton.ac.uk/id/eprint/367441
ISSN: 0003-2700
PURE UUID: cf6aa59e-873c-4b20-899d-3414757c680f
ORCID for Guy Denuault: ORCID iD orcid.org/0000-0002-8630-9492

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Date deposited: 30 Jul 2014 09:43
Last modified: 07 Oct 2020 01:36

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Contributors

Author: Mara Serrapede
Author: Giovanni Luca Pesce
Author: Richard J. Ball
Author: Guy Denuault ORCID iD

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