Scanning electrochemical cell microscopy for the study of (nano)particle electrochemistry: From the sub?particle to ensemble level

Scanning electrochemical cell microscopy (SECCM) is a scanning-droplet-based technique that allows fluxes and/or interfacial reactivity to be measured and visualized with high spatiotemporal resolution. This minireview spotlights the use of SECCM for studying electrochemistry (nano)particles, highlighting recent works spanning multiple timescales (i.e., microseconds seconds) lengthscales nanometers micrometers) probe physicochemical phenomena at sub-particle, single particle, (micro)ensemble levels. In SECCM, (nano)particles (or small particle ensembles) are electrochemically interrogated—directly from colloidal solution by investigating nanoimpacts substrate electrode) or supported on an inert support electrode—with pipette operated in either stationary (point measurement) dynamic scanning/imaging mode. Nanoscale-resolved information (e.g., local rates electron- ion-transfer, catalytic activity, corrosion resistance, etc.) readily related (nano)particle structure properties, collected commensurate scale complementary, co-located microscopy/spectroscopy techniques, allowing function resolved directly unambiguously down sub-particle level. Understanding structure?function this enables macroscopic “particle-on-support” electrode behavior rationalized further predicted, guiding discovery, design, engineering novel electromaterials enhanced function, which “holy grail” materials science.