A Versatile Heterometallic Microporous MOF for Photocatalytic Hydrogen Generation

Photocatalytic particulate systems offer a cost‐effective solar hydrogen production but are generally limited by narrow visiblelight absorption and poor stability. Here, we report a family of heterometallic MOF, MIP215(Zr IV /M II ) (M II = Cu, Ni), constructed from 8‐connected Zr 6 oxoclusters and 4‐connected pyrazolate–carboxylate metalloligands using a onepot, ambient, water only synthesis. The resulting 4,8‐connected scu frameworks feature one‐dimensional microporous channels, chemical robustness in aqueous and organic media, and reversible solvent‐responsive flexibility upon dehydration/rehydration. Both Cu or Ni based solids exhibit broad visible absorption range up to ca . 800 nm, and suitable band‐edge positions for H 2 evolution in water/methanol under simulated sunlight. In the absence of any cocatalyst, MIP215(Zr/Cu) delivers sustained activity exceeding 1 mmol·g − 1 H 2 in 5 h, while MIP215(Zr/Ni) displays higher initial rates but reduced stability, in line with observed metalleaching and crystallinity loss. Time‐dependent density functional theory calculations indicate that ligand‐to‐metal charge‐transfer states localized on the metalloligands govern the photocatalytic response, underscoring the role of photophysics beyond thermodynamic driving force in the superior Cu‐based performance. This work establishes a green and scalable approach to robust, flexible heterometallic MOFs with tunable photoactivity for efficient, noblemetalfree solar hydrogen production.