Understanding the Oxygen Evolution Reaction Mechanism Through the Lens of Scanning Electrochemical Microscopy.

Scanning electrochemical microscopy (SECM) is an efficient operando technique that offers deep insight into the electrode-electrolyte interfacial process occurring during electrochemical reactions. This approach helps to identify the complexities of the reactions associated with the electrochemical steps and intermediates in various reaction conditions. This article focuses on employing SECM as a tool to study anodic oxygen evolution reaction (OER) in water splitting. Using this technique, the qualitative and quantitative evaluation of catalytic activity can be mapped on catalyst surface. This work critically investigates SECM's strengths in probing key catalytic parameters involved in OER, such as charge transfer kinetics, oxygen flux evaluation, and catalyst-substrate interactions. In addition to that, SECM's ability to detect reactive oxygen species, active site analysis, and determination of catalyst oxidation state are also emphasized, using various operational modes. Finally, the challenges of SECM are highlighted elaborately, which can pave the path for further innovation in related fields.