Zihua Zhu oral presentation (PB3-Thu1-2-4)
Molecular Characterization of Electric Double Layer at Electrode-Electrolyte Interface Using In Situ Liquid SIMS
1 Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 3335 Innovation Blvd., P.O. Box 999, WA 99352 Richland, United States
2 Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, 3335 Innovation BLVD, WA 99354 Richland, United States
Abstract: An electric double layer is expected to form if a potential is applied on an electrode.1 Formation of electric double layer is generally prior to occurring of electrochemical reactions on the electrode-electrolyte interface, and the structure of electric double layer may greatly affect the following electrochemical processes. Therefore, characterization of electric double layer at a molecular level is of great interest. However, most experimental investigations of electric double layer based on traditional electrochemical methods only provide indirect evidence. Little direct molecular evidence has been reported. The major reason is that the thickness of the electric double layer is generally believed in a range of 0.2 - 20 nanometers, but very few operando characterization techniques can provide molecular information with such a spatial resolution. During the last several years, we developed in situ liquid SIMS technique, and applied it on characterization of electrochemical processes at electrode-electrolyte interface.2-4 Recently, we used in situ liquid SIMS to successfully monitor formation and dynamics of electric double layer at a molecular level.5,6 In this presentation, design and fabrication of a vacuum compatible electrochemical cell for in situ liquid SIMS analysis, optimization of experimental conditions for various liquid samples and two examples of application of in situ liquid SIMS on molecular characterization of electric double layer will be discussed. In addition, development history and future perspective of in situ liquid SIMS will be briefly addressed. With a combination of operando characterization, providing of molecular information and super depth resolution, in situ liquid SIMS opens a new door to investigate complex chemistries occurring at electrode-electrolyte interface.
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