Understanding the structure–activity relationship
at electrochemical
interfaces is crucial in improving the performance of practical electrochemical
devices, ranging from fuel cells, electrolyzers, and batteries to
electrochemical sensors. However, functional electrochemical interfaces
are often complex and contain various surface structures, creating
heterogeneity in electrochemical activity. In this Perspective, we
highlight the role of heterogeneity in electrochemistry, especially
in the context of electrocatalysis. Current methods for revealing
the heterogeneity at electrochemical interfaces, including nanoelectrochemistry
tools and single-entity approaches, are discussed. Lastly, we provide
perspectives on what one can learn by studying heterogeneity and how
one can use heterogeneity to design more efficient electrochemical
devices.