Prospects for electrochemical X-ray photoelectron spectroscopy as a powerful electrochemical interface characterization technique

X-ray spectroscopies provide a powerful way to disentangle the roles of the different elements in electrochemical systems. Within this family of spectroscopies, electrochemical X-ray photoelectron spectroscopy (EC-XPS) has recently emerged as a technique that can specifically probe the heart of any electrochemical process: the electrode-electrolyte interface. Here, we discuss the current state -of -the -art of EC-XPS and review the practical implementation of the measurements. We identify three principal categories of EC-XPS approaches: quasi -in situ, thin electrolyte, and thin electrode. As each presents distinct advantages and drawbacks, we highlight the importance of matching the electrochemical system of interest with the most suitable approach.