Understanding fundamentals of electrochemical reactions with tender X-rays: A new lab-based operando X-ray photoelectron spectroscopy method for probing liquid/solid and gas/solid interfaces across a variety of electrochemical systems

Electrocatalysis is key to improving energy efficiency, reducing carbon emissions, and providing a sustainable way of meeting global needs. Therefore, elucidating electrochemical reaction mechanisms at the electrolyte/electrode interfaces essential for developing advanced renewable technologies. However, direct probing real-time interfacial changes, i.e., surface intermediates, chemical environment, electronic structure, under operating conditions challenging necessitates use in situ methods. Herein, we present new lab-based instrument commissioned perform analysis liquid/solid using ambient pressure X-ray photoelectron spectroscopy (APXPS). This setup takes advantage chromium source tender X-rays designed study by “dip pull” method. Each main components was carefully described, results performance tests are presented. Using three-electrode setup, system can probe intermediate species potential shifts across liquid electrolyte/solid electrode interface. In addition, demonstrate how this allows changes gas/solid case study: sodium–oxygen model battery. APXPS studies still early stages, so summarize current challenges some developmental frontiers. Despite challenges, expect that joint efforts improve instruments will enable us obtain better understanding composition–reactivity relationship realistic conditions.