Learning from the Heterogeneity at the Electrode-Electrolyte Interface from Nanoelectrochemistry

Electrochemical interfaces are often complex and abundant with a variety of structures. This heterogeneity often impedes the interpretation of the structure-activity relationship from ensemble electrochemical measurements. Nanoelectrochemistry and single-entity electrochemistry have revealed this heterogeneity in the past decade. In this talk, I will discuss our efforts toward learning new knowledge from the heterogeneity at the electrochemical interface in electrocatalysis and electrodeposition using scanning electrochemical cell microscopy (SECCM) coupled with colocalized characterization. In addition, in order to probe how the local structure affects the local product selectivity in electrocatalytic reactions, we have integrated the benefits of SECCM with scanning electrochemical microscopy (SECM) in a dual-channel nanopipette. Using this probe, we mapped the activity and selectivity in oxygen reduction reaction (ORR) on polycrystalline Au and showed facet-dependent selectivity towards generating H2O2. Lastly, the measurement of site-specific nucleation kinetics and energetics during electrodeposition will be discussed.