Single-entity electrochemistry: Unveiling nanoparticle behavior with advanced scanning probe electrochemical techniques

The advancement of sophisticated electroanalytical techniques has attracted significant interest in investigating the fundamental properties of individual nanoparticles. This review highlights recent developments in scanning probe microscopy (SPM), including scanning electrochemical cell microscopy (SECCM), electrochemical scanning tunneling microscopy (EC-STM), and electrochemical atomic force microscopy (EC-AFM). These SPM techniques provide complementary insights into nanoparticle size, morphology, electronic structure, and surface reactivity. SECCM enables localized electrochemical analysis with high spatial resolution, while EC-STM and EC-AFM facilitate nanoscale imaging and the identification of active sites involved in electrocatalytic reactions. One of the most promising strategies involves integrating these techniques to establish structure–activity correlations at the single-nanoparticle level, thereby enhancing characterization capabilities. We demonstrate how hybrid characterization techniques can be employed to capture in situ information during complex electrochemical processes at the electrode–electrolyte interface. Specifically, we highlight the monitoring and measurement of local electrochemical processes using high-spatial-resolution imaging in correlation with single-entity electrochemistry techniques.