A Novel Ti ₁₂ ‐Based Metal‐Organic Framework for Photocatalytic Hydrogen Evolution

Abstract A new microporous titanium‐based metal‐organic framework (Ti‐MOF), labeled as MIP‐209(Ti) (MIP: Materials from Institute of Porous Materials of Paris), features nitro terephthalate ligands and Ti ₁₂ O ₁₅ oxo‐clusters, as revealed by continuous rotation electron diffraction (cRED). MIP‐209(Ti) can be obtained using two different terephthalate (1, 4‐BDC ²⁻ ) derivatives such as NO ₂ ‐BDC and 2Cl‐BDC in an eco‐friendly solvent, suggesting the isostructural versatility of Ti ₁₂ ‐MOFs. Alternatively, its Ti‐oxo‐cluster can be tuned, similarly to MIP‐177(Ti)‐LT bearing the same Ti ₁₂ O ₁₅ sub‐unit. Typically, low percentage Cr ³⁺ doping (≤5 at%) in MIP‐209(Ti) favorably enhances the water stability. MIP‐209(Ti‐Cr)‐NO ₂ shows a significant hydrogen production rate, with good reusability and stability under simulated solar light irradiation. Compared to the benchmark Ti‐MOF IEF‐11, the hydrogen production of MIP‐209(Ti‐Cr)‐NO ₂ with 5 at% Cr doping has a fourfold enhancement in photocatalytic hydrogen evolution from water splitting reaction (HER) during 5 h in presence of methanol (5 812 µ mol/g _cat against 1 391 µ mol/g _cat ), as well as, without any noble metal co‐catalyst, a sixfold enhancement in overall water splitting reaction (OWS) (681 and 325 µ mol/g _cat of H ₂ and O ₂ , respectively, against 94 and 53 µ mol/g _cat of H ₂ and O ₂ , respectively). This work represents a leap forward in the synthesis of Ti‐MOFs and their practical photocatalytic applications.