Molecular linker control of activity and stability in metal-organic frameworks for water splitting

Metal-organic frameworks (MOFs) have attracted significant research interest as a versatile class of electrocatalysts toward water splitting owing to their unique properties; however, they still fail to meet the requirements for industrial applications. To boost their electrocatalytic performance, extensive efforts have mainly focused on metal-node engineering, which primarily tunes the intrinsic activity of metal-active sites, yet the remaining drawback is their instability feature as electrocatalysts. Despite significant achievements, this metal-centric viewpoint overlooks the critical role of organic linkers, which constitute an integral part of the MOF backbone and directly influence the electronic structure, coordination environment, and physicochemical properties of metal nodes. This mini-review systematically summarizes recent advances in linker engineering-enabled MOFs as electrocatalysts for efficient water splitting, highlighting key design strategies including functional group modification linkers, π-conjugated linkers, redox-active linkers, heteroatom-doped linkers, mixed linkers and defect linkers. By understanding the correlation between fundamental principles and material characteristics, their resulting impacts of linker design on electrocatalytic activity toward water splitting are critically analyzed. Furthermore, current challenges and future perspectives are outlined, focusing on improving electrical conductivity, long-term stability under harsh electrochemical conditions, and scalable synthesis. This study aims to provide comprehensive insights and practical guidelines for the application of linker engineering in sustainable electrochemical hydrogen production.