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

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• 作者：Marcel Risch ; Kelsey A. Stoerzinger ; Tom Z. Regier ; Derek Peak ; Sayed Youssef Sayed ; Yang Shao-Horn
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 20, 2015
• 年：2015
• 卷：119
• 期：33
• 页码：18903-18910
• 全文大小：426K
• ISSN：1932-7455

文摘

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 脳 10¹¹ s^鈥? mm^鈥?, 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^鈥? mm^鈥?. 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.