Development of Operando Observation Technique of Electrochemical Reactions at the Solid-Liquid Interface by Fluorescence-yield Wavelength-dispersive Soft X-ray Absorption Spectroscopy

Abstract

Real-time observation of an electrochemical reaction at a solid–liquid interface was performed using fluorescence-yield wavelength-dispersive soft X-ray absorption spectroscopy (XAS). A dedicated electrochemical cell was prepared for this study. As a model experiment, an electrochemical oxygen evolution reaction (OER) was observed in alkaline solution (0.1 M NaOH) on the surface of a Pt thin film working electrode. With positive potential shift, the XAS signal at K-edge of oxygen, whose peak position is close to that of gas-phase O2, increased in correlation with the electrode potential. This method has potential as a real-time observation method for time-dependent processes in various fields using electrochemical reactions at the solid–liquid interface, especially electrochemical catalytic reactions.