Designing Better Electrocatalysts via Ion Exchange for Water Splitting

Abstract Green hydrogen, produced through electrocatalytic water splitting, stands as a promising clean energy source for future large‐scale applications. Significant efforts have been dedicated to advancing high‐performance electrocatalysts for the oxygen evolution reaction and the hydrogen evolution reaction. Ion exchange, a widely adopted technology, facilitates the chemical transformation of materials by substituting the cations or anions in original electrocatalysts with guest ions. By finely tuning the atomic structure of electrocatalysts, ion exchange enables leveraging strengths and compensating for weaknesses. This review begins with an exploration of the fundamentals of water splitting and ion exchange reactions, stating the regulatory impact of ion exchange on performance. Special emphasis is placed on distinguishing the structural characteristics of different electrocatalysts in the context of ion exchange. The review also underscores the significance of reaction conditions for ion exchange, revealing their dynamic effects. Finally, the review proposes perspectives aimed at inspiring further research efforts to design novel electrocatalysts beyond applying in water splitting.