Reversibility of Ferri-/Ferrocyanide Redox during Operando Soft X‑ray Spectroscopy

The ferri-/ferrocyanide redox couple is ubiquitous in many fields of physical chemistry. We studied its photochemical response to intense synchrotron radiation by in situ X-ray absorption spectroscopy (XAS). For photon flux densities equal to and above 2 × 1011 s–1 mm–2, precipitation of ferric (hyd...

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Bibliographic Details
Published in:Journal of physical chemistry. C 2015-08, Vol.119 (33), p.18903-18910
Main Authors: Risch, Marcel, Stoerzinger, Kelsey A, Regier, Tom Z, Peak, Derek, Sayed, Sayed Youssef, Shao-Horn, Yang
Format: Article
Language:English
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Summary:The ferri-/ferrocyanide redox couple is ubiquitous in many fields of physical chemistry. We studied its photochemical response to intense synchrotron radiation by in situ X-ray absorption spectroscopy (XAS). For photon flux densities equal to and above 2 × 1011 s–1 mm–2, precipitation of ferric (hydr)­oxide from both ferricyanide and ferrocyanide solutions was clearly detectable, despite flowing fast enough to replace the solution in the flow cell every 0.4 s (flow rate 1.5 mL/min). During cyclic voltammetry, precipitation of ferric (hydr)­oxide was promoted at reducing voltages and observed below 1011 s–1 mm–2. This was accompanied by inhibition of the ferri-/ferrocyanide redox, which we probed by time-resolved operando XAS. Our study highlights the importance of considering both electrochemical and spectroscopic conditions when designing in situ experiments.
ISSN:1932-7447
1932-7455
DOI:10.1021/acs.jpcc.5b04609