ABSTRACT
Enabled by the development of nanometer-sized electrochemical probes, SECM has become a powerful technique for studying electrochemical systems and processes on the nanoscale. This chapter describes fundamentals of and recent advances in nanoscale SECM. Nanopipette-based tips have been extensively used in SECM experiments. Essentially flat and layered materials are the most suitable objects for nanoscale SECM imaging. A small tip can be brought within the nm-range distance from the surface of such a substrate and scanned over it in the x-y plane without colliding with protruding topographic features. SECM experiments discussed include measurements of heterogeneous electron transfer at the metal/solution interface and characterization of surface reactivity of two-dimensional (2D) electrocatalysts. The nm size of an SECM tip is essential for high-resolution characterization of heterogeneous surface reactivity of 2D materials and localization of active sites. Visualizing and characterizing activities of the active sites is particularly difficult when their size is on the atomic scale.
