Leenheer, Andrew J. and Atwater, Harry A. (2012) Imaging Water-Splitting Electrocatalysts with pH-Sensing Confocal Fluorescence Microscopy. Journal of the Electrochemical Society, 159 (9). H752-H757. ISSN 0013-4651. doi:10.1149/2.022209jes. https://resolver.caltech.edu/CaltechAUTHORS:20121106-100653685
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Abstract
Hydrogen generation by water electrolysis is promising for energy storage, and imaging the reaction dynamics near a H_2-evolving electrode can provide valuable insights. We utilized laser-scanning confocal fluorescence microscopy to map the product/reactant concentration at a H_2-evolving electrode at micron-scale resolution which identifies areas with fast reaction kinetics. Small concentrations of a pH indicator dye added to the aqueous electrolyte enables ratiometric fluorescence sensing for quantitative pH detection over the range pH 5.3-7.5 and minimally perturbs the local environment. To overcome diffusion limitations, a miniature flow cell was utilized in the microscope to achieve micron-scale resolution in steady state while applying galvanostatic current. We demonstrated the technique using F:SnO_2-coated glass with varied metal catalyst patterns and compositions resulting in clear images of increased pH near areas of high water-reducing activity. Simulations of the pH profiles near the electrolyte-patterned catalyst interface were also performed using the COMSOL finite-element software package to solve the convection/diffusion equations, and the calculation results agreed well with the experimentally-observed fluorescence profiles. Flow cell fluoresecence microscopy shows promise in imaging comparative catalyst activity as well as three-dimensional product/reactant profiles in complex electrode architectures.
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Additional Information: | © 2012 The Electrochemical Society. Manuscript submitted April 23, 2012; revised manuscript received June 19, 2012. Published August 14, 2012. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. We thank V. Ferry and J. McKone for helpful discussions. References | |||||||||
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Issue or Number: | 9 | |||||||||
DOI: | 10.1149/2.022209jes | |||||||||
Record Number: | CaltechAUTHORS:20121106-100653685 | |||||||||
Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20121106-100653685 | |||||||||
Official Citation: | Andrew J. Leenheer and Harry A. Atwater Imaging Water-Splitting Electrocatalysts with pH-Sensing Confocal Fluorescence Microscopy J. Electrochem. Soc. 2012 159(9): H752-H757; doi:10.1149/2.022209jes | |||||||||
Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | |||||||||
ID Code: | 35296 | |||||||||
Collection: | CaltechAUTHORS | |||||||||
Deposited By: | Tony Diaz | |||||||||
Deposited On: | 12 Nov 2012 19:05 | |||||||||
Last Modified: | 09 Nov 2021 23:14 |
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