In situ Infrared Spectroelectrochemistry for Understanding Structural Transformations of Precisely Defined Ions at Electrochemical Interfaces

Journal Article · Tue Sep 18 04:00:00 EDT 2018 · Analytical Chemistry

DOI:https://doi.org/10.1021/acs.analchem.8b02440· OSTI ID:1558424

Su, Pei ^[1]; Prabhakaran, Venkateshkumar ^[2]; Johnson, Grant E. ^[2]; Laskin, Julia ^[1]

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1. Purdue University
2. BATTELLE (PACIFIC NW LAB)

Understanding the intrinsic properties of electroactive species at electrode-electrolyte interfaces (EEIs) is essential to the rational design of high-performance solid-state energy conversion and storage systems. In situ spectroscopy combined with cyclic voltammetry (CV) provides insights into structural changes of electroactive species at functioning EEIs. Ion soft-landing enables precisely-controlled deposition of massand charge-selected ions onto electrode surfaces thereby avoiding the contamination inherent with conventional electrode preparation techniques. In this contribution, we describe a new approach for the simultaneous electrochemical and spectroscopic characterization of soft-landed ions at operating solid-state EEIs. The technique exploits a specially-fabricated three-electrode cell that is compatible with in situ infrared reflection absorption spectroscopy (IRRAS) characterization of the softlanded ions. Keggin polyoxometalate (POM) anions, PW12O40 3-, were selected as a model system for these experiments due to their multielectron redox activity, structural stability, and well-characterized IRRAS spectrum. In situ CV measurements indicated continuous multielectron transfer processes of the soft-landed PW12O40 3- anions over a large potential range of -2.1 to -0.3 V. A distinct shift in the wavenumber of the terminal W=Ot stretching vibration in the IRRAS spectra was observed during the multielectron reduction process. The results demonstrate the capabilities of the in situ spectroelectrochemical approach for examining structural changes of well-defined electroactive species during electron transfer processes at operating solid-state EEIs.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1558424
• Report Number(s): PNNL-SA-137370
• Journal Information: Analytical Chemistry, Journal Name: Analytical Chemistry Journal Issue: 18 Vol. 90
• Country of Publication: United States
• Language: English