This review highlights the principles, recent advances, and emerging applications of Scanning Electrochemical Microscopy (SECM) in electrocatalysis. We discuss its use in carbon dioxide and oxygen electrocatalysis, the detection of short-lived intermediates, and provide a framework for its implementation in investigations of electrocatalytic interfaces.

Abstract

Understanding local surface reactivity in the mechanism of electrocatalytic reactions has become particularly important for designing efficient electrocatalytic systems for renewable energy conversion. The dynamic formation of species near the electrode surface compared to the bulk may lead to the formation of key intermediates, making understanding reaction mechanisms challenging. In this review, we highlight the capabilities of scanning electrochemical microscopy (SECM) as an interfacial characterisation tool for the in situ analysis of electrocatalytic reactions. First, we introduced the basic concepts of SECM. Then we discussed how SECM characterisation leads to a deeper understanding of the local reactivity in electrochemical reactions, including carbon, oxygen, and short-lived intermediates electrocatalysis. We highlight emerging applications of SECM, such as high-resolution spatial mapping of nanoscale electrocatalytic activity, high-throughput screening, and its combination with spectroscopic techniques. We illustrate how SECM investigations are key in electrocatalysis, offering powerful capabilities for in situ analysis, local activity mapping, and coupling with complementary methods to uncover mechanistic pathways.