Recent Advances in X-ray Absorption Spectroscopy and Combined Techniques for Electrocatalytic Water Splitting

Revealing and clarifying the internal chemical reaction processes and mechanisms of electrocatalysts would be of great help to the performance modulation for electrocatalysts. Over the past decade, advanced characterization techniques based on synchrotron radiation (SR) have accelerated the development of various electrocatalysts. SR is an advanced, high-intensity, collimated source with unique advantages for characterizing material structures at atomic or molecular scale. This review systematically summarizes the most widely used and important SR technique, X-ray absorption spectroscopy (XAS), for electrocatalyst research. Notably, combined techniques are increasingly being employed in the characterization of electrocatalysts, which bring new perspectives to this area. Special focus is placed on how these characterization techniques are used to understand the reaction mechanisms of electrocatalysts and reveal the reconstruction phenomena during the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), thereby enhancing the practical performance. Finally, based on the current state of SR technology development, the challenges and future opportunities for SR technology in electrocatalyst research are outlined.