Solvent-Directed Assembly and Transition-Metal Functionalization of a Two-Dimensional Indium Chalcogenide Framework

Two-dimensional (2D) chalcogenide frameworks built from supertetrahedral clusters offer tunable architectures and postsynthetic flexibility. Open-framework chalcogenides are commonly synthesized at elevated temperatures. Exploring their synthesis under mild conditions can allow access to a greater range of materials and properties. Here, we report an amine- and solvent-directed strategy to selectively construct 1D, 2D, and 3D indium sulfide frameworks from the same precursors by solvent modulation. Among them, the 2D framework T2-InS-AEP features accessible interlayer space that enables postsynthetic incorporation of transition-metal ions (Fe, Co, Ni) through mild chloride-mediated etching and ion exchange. The resulting chalcogenide-derived materials retain crystallinity while exhibiting tunable compositions. Electrochemical studies reveal that Ni- and Co/Ni-modified derivatives show significantly enhanced oxygen evolution reaction (OER) performance, with the best materials achieving activities comparable to benchmark IrO₂. This work highlights a generalizable approach to the modular design and functionalization of 2D chalcogenide frameworks.