[2Dp01-08] Advancement of experimental techniques for surface analysis using synchrotron radiation and its applications: Synchrotron Radiation Surface Science Division's Session

[2Dp03] Real-time observation of chemical reactions at surface and solid-liquid interface by wavelength-dispersive soft X-ray absorption spectroscopy

*Kaoruho Sakata¹, Kenta Amemiya¹ (1. Institute of Materials Structure Science, High Energy Accelerator Research Organization)

X-ray absorption spectroscopy (XAS) in the soft X-ray region is one of the useful methods to analyze the chemical properties near surface, however, to observe the reaction change over time without halting the reaction is difficult with conventional method. To overcome the disadvantage of measurements, we developed a method to illuminate the sample with dispersed soft X rays and separately collecting the fluorescent X-ray emitted at each position on the sample and succeeded to realize real-time observation. The method can also be applied for the observation of chemical reactions under the near ambient pressure air and external fields (magnetic and electric fields), because the detection of soft X-ray fluorescence has recently been realized. In this study, aiming for the observation under near-ambient gas pressure, we observed the surface oxidation of Co and Cu thin film, which proceeds to depth direction in real time. For another application example of the method, we applied it to observe the chemical states at the solid–liquid interface directly in real time and operando during the electrochemical oxygen evolution reaction for water splitting.