Electrochemically Induced pH Change: Time-Resolved Confocal Fluorescence Microscopy Measurements and Comparison with Numerical Model

Nakul Pande*, Shri Kannan Chandrasekar, Detlef Lohse, Guido Mul, Jeff Wood, Bastian Timo Mei*, Dominik Krug*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Confocal fluorescence microscopy is a proven technique, which can image near-electrode pH changes. For a complete understanding of electrode processes, time-resolved measurements are required, which have not been achieved previously. Here we present the first measurements of time-resolved pH profiles with confocal fluorescence microscopy. The experimental results compare favorably with a one-dimensional reaction–diffusion model; this holds up to the point where the measurements reveal three-dimensionality in the pH distribution. Specific factors affecting the pH measurement such as attenuation of light and the role of dye migration are also discussed in detail. The method is further applied to reveal the buffer effects observed in sulfate-containing electrolytes. The work presented here is paving the way toward the use of confocal fluorescence microscopy in the measurement of 3D time-resolved pH changes in numerous electrochemical settings, for example, in the vicinity of bubbles.
Original languageEnglish
Pages (from-to)7042-7048
Number of pages7
JournalThe journal of physical chemistry letters
Issue number17
Publication statusPublished - 3 Sept 2020


  • UT-Hybrid-D
  • fluorescence
  • Electrical properties
  • Electrodes
  • Electrolytes
  • dyes and pigments

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