Harnessing disorder: amorphous nanostructure for electrocatalytic oxygen evolution reaction

The oxygen evolution reaction (OER) is a critical bottleneck in water electrolysis, making the development of highly active electrocatalysts essential for efficient hydrogen production. Notably, in-situ amorphization has been observed on electrocatalyst surfaces during OER process, often accompanied by enhanced activity upon initial electrochemical activation, which highlights the pivotal role of surface amorphous reconstruction in promoting OER performance. However, the evolution of surface amorphous layers is highly dynamic and complex, frequently resulting in diverse structural configurations. Therefore, understanding the amorphization process and elucidating the roles of amorphous nanostructures are crucial for establishing structure-activity relationships and guiding the development of electrocatalysts. Previous reviews on amorphous electrocatalysts have mainly focused on their overall disordered structural features and general electrocatalytic behavior, whereas this review emphasizes the role of short/medium-range structural motifs in electrocatalytic performance. Concretely, this review begins by introducing the phenomenon and mechanisms of surface amorphous reconstruction during OER process, followed by a discussion of structure-activity relationships in amorphous nanostructures, with a focus on short/medium-range motifs. Next, recent advances in the OER performance of amorphous nanomaterials are reviewed. Finally, current challenges and future opportunities for amorphous electrocatalysts are highlighted. This review aims to provide guidance for the rational design of amorphous OER nanomaterials.