Microscopic Measurement of pH with Iridium Oxide Microelectrodes

Wipf, David O.; Ge, Fuyun; Spaine, Thomas W.; Baur, John E.

doi:10.1021/ac000383j

Cited by 97 publications

(88 citation statements)

References 37 publications

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“…[30][31][32] In order to extract reliable information, different constraints have to be considered. On the one hand, the electrochemical cell has to be contained within a microscopic volume, which requires not only the use of small electrodes (i.e.…”

Section: -29mentioning

confidence: 99%

Fountain pen for scanning electrochemical microscopy

et al. 2010

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A fountain pen probe has been developed to extend the scope of scanning electrochemical microscopy (SECM) experiments to dry surfaces. The fountain pen is fabricated by UV-photoablation of a polyethylene terephthalate (PET) film and consists on one side of one microchannel for flowing an electrolyte solution to the open tip, integrating a reference/counter electrode and on the other side a carbon track. The exposed tip of the track forms the working electrode located close to the microchannel outlet. The fountain pen can operate in a pointillist mode where a nanolitre droplet at the bottom of the probe connects it to a well-defined surface area to study locally the substrate, but can also operate in a scanning mode leaving a linear wet track of solution behind it to monitor the surface activity. The electrochemical characterization of the proposed fountain pen probe was performed by cyclic voltammetry, approach curves and lateral line scans over insulating and conductive substrates, showing that the flow rate and the probe-substrate distance have a major influence on its electrochemical behavior. An SECM image of a gold on glass EPFL logo is presented as a proof-ofconcept that fountain pen probes can be employed for the detection of surface activity when scanning in a contact regime.

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Section: -29mentioning

confidence: 99%

Fountain pen for scanning electrochemical microscopy

et al. 2010

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“…When deployed as the tip in scanning electrochemical microscopy (SECM), these electrodes have enabled the measurement of pH with high spatial resolution at interfaces. [11][12][13][14] The scale on which pH electrodes can be made has advanced in recent years to the micro 15,16 and nano scale. 17,18 SECM pH probes employing a variety of metal/metal oxides have been reported previously.…”

Section: Introductionmentioning

confidence: 99%

“…17,18 SECM pH probes employing a variety of metal/metal oxides have been reported previously. 15,[19][20][21] Iridium oxide-based pH ultramicroelectrodes have proven particularly popular for spatially resolved pH measurements in SECM, owing to their fast response time, long termstability over a wide range of pHs, temperatures and pressures, all-solid format and capability for miniaturization. 15,22,23 Iridium oxide pH electrodes have been prepared by either electrochemical oxidation, 22 thermal decomposition 24 and sputter deposition 25 of iridium metal, or by the electrodeposition of iridium oxide from alkaline solutions of iridium salts.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping

et al. 2013

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(2013) Fabrication and characterization of dual function nanoscale pH-scanning ion conductance microscopy (SICM) probes for high resolution pH mapping. Analytical Chemistry, Volume 85 (Number 17). pp. 8070-8074 Permanent WRAP url: http://wrap.warwick.ac.uk/57249 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work of researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-forprofit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work http://dx.doi.org/10.1021/ac401883n The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. AbstractThe easy fabrication and use of nanoscale dual function pH-scanning ion conductance microscopy (SICM) probes is reported. These probes incorporate an iridium oxide coated carbon electrode for pH measurement and an SICM barrel for distance control, enabling simultaneous pH and topography mapping. These pH-SICM probes were fabricated rapidly from laser pulled theta quartz pipets, with the pH electrode prepared by in-situ carbon filling of one of the barrels by the pyrolytic decomposition of butane, followed by electrodeposition of a thin layer of hydrous iridium oxide. The other barrel was filled with an electrolyte solution and Ag/AgCl electrode as part of a conductance cell for SICM. The fabricated probes, with pH and SICM sensing elements typically on the 100 nm scale, were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and various electrochemical measurements. They showed a linear super-Nernstian pH response over a range of pH (pH 2-10). The capability of the pH-SICM probe was demonstrated by detecting both pH and topographical changes during the dissolution of a calcite microcrystal in aqueous solution. This system illustrates the quantitative nature of pH-SICM imaging, because the dissolution process changes the crystal height and interfacial pH (compared to bulk) and each is sensitive to the rate. Both measurements reve...

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“…In the case of the flat film, Fig. 4A, the reflectivity spectrum (normalized to 5 the reflectivity from an aluminum mirror) changes in intensity with angle of incidence but does not change in wavelength or shape. For the structured film, Fig.…”

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confidence: 99%

Electrodeposition of highly ordered macroporous iridium oxide through self-assembled colloidal templates

et al. 2009

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Iridium oxide electrodeposited through a self-assembled colloidal template has an inverse opal structure. Monolayers present long range hexagonal arrangements of hemispherical nanocavities while multilayers present 3D honeycomb structures with spherical voids. The films are amorphous, 10 have several electroactive redox states and are electrochromic. The nanostructure modifies their reflectivity thus indicating these films could be used as tunable photonic devices.

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Microscopic Measurement of pH with Iridium Oxide Microelectrodes

Cited by 97 publications

References 37 publications

Fountain pen for scanning electrochemical microscopy

Fountain pen for scanning electrochemical microscopy

Fabrication and Characterization of Dual Function Nanoscale pH-Scanning Ion Conductance Microscopy (SICM) Probes for High Resolution pH Mapping

Electrodeposition of highly ordered macroporous iridium oxide through self-assembled colloidal templates

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