The rise of electrochemical surface science: From in situ interface structure to operando dynamics

Surface science studies of electrochemical interfaces and processes have gained increasing popularity in the last decades, owning to the increasing importance of electrochemistry for key technologies of the 21th century, especially in electric energy storage and conversion. In situ and operando surface-sensitive methods, such as scanning probe microscopy and surface X-ray diffraction, as well as complementary ab initio theory can provide atomic-scale information on solid electrode surface in contact with liquid electrolytes, including structural changes under reaction conditions. The level of detail obtainable by these approaches is illustrated in this short review for selected examples. These include the adsorption of sulfate and other oxyanions, where a crucial role of coadsorbed water is found, the restructuring of Cu electrode surfaces under hydrogen evolution and CO₂ reduction conditions, and the mechanisms of electrochemical Pt oxidation and its correlation with Pt dissolution.