Electrochemical tip-enhanced Raman spectroscopy for in situ study of electrochemical systems at nanoscale

Identifying the active sites and revealing the dynamic evolution of relevant active species are the key to deeply understanding electrocatalytic processes, which may facilitate the rational design of catalysts and improve the electrochemical performance of catalysts. However, achieving these goals requires advanced characterization techniques with high spatial resolution and that can provide chemical fingerprint information of the surface species. Electrochemical tip-enhanced Raman spectroscopy (EC-TERS), which is able to simultaneously obtain chemical information and surface morphology, is a promising technique for the above purpose. This review first summarizes the current understanding of catalytic active sites. Then, we introduce the basic principle of EC-TERS, the challenges for developing the EC-TERS instruments, and recent applications of EC-TERS in electrocatalytic processes. Finally, we give perspectives for the future development of EC-TERS.