Single-Atom Catalysts for Oxygen Evolution Reaction

In the electrochemical process, the oxygen evolution reaction (OER) plays a crucial role by providing protons and electrons for cathodic reactions such as the hydrogen evolution reaction (HER) or carbon dioxide reduction reaction (CO2RR). Since OER is the bottleneck of the electrochemical processes, it requires an active and durable catalyst that can generate high OER current density at minimum overpotential. In this context, single-atom catalysts (SACs) hold great promise for achieving significant catalytic mass activity by precisely utilizing metal active sites at the atomic level. However, SACs face a challenge where smaller particles tend to aggregate into clusters or larger particles due to their high surface energy. Consequently, it becomes imperative to gain a comprehensive understanding of the role of support materials, their interactions with SACs, and the behavior of SACs under OER conditions. This book chapter is dedicated to an exploration of recent advancements in the application of SACs for the OER. It encompasses a thorough examination of the structural characterization of SACs and delves into the utilization of in situ/operando spectroscopic techniques and computational research to uncover the underlying mechanisms responsible for their catalytic activity. Furthermore, the chapter provides a comprehensive summary of the OER catalytic activity and the stability of SACs, offering valuable insights into the current state of SAC technology.