Ligand removal in Ti-MOFs: Unlocking the potential of Pt nanoparticles for the selective hydrogenation of furfural

Due to their highly tunable structures and porous nature, metal-organic frameworks (MOFs) have garnered substantial interest as versatile platforms for immobilizing noble metal nanoparticles in selective hydrogenation catalysis. However, the inherent limitations of MOFs, such as small micropores and weak interactions between inorganic nodes and guest noble metals (caused by organic ligands), often result in limited accessibility and the collapse of reactive sites. To overcome these challenges, this study focuses on a novel partial deligandation strategy and further, stabilizes the active Pt nanoparticles over it. Specifically, Ti-MOF-250 was synthesized by partially decomposing NH₂–Ti-MIL-125 (Ti-MOF) at 250 °C, followed by the eco-friendly polyol reduction method to produce Pt/Ti-MOF-250 catalyst. Compared to the non-deliganded Ti-MOF, the Ti-MOF-250 catalyst, which retains residual organic ligands, exhibits a greater surface area, a hierarchical porous structure, and active defect sites that expose the unsaturated Ti metal centers. These features synergistically control the Pt particle size, enhance their uniform dispersion, and increase the number of exposed reactive sites. The distinctive structural properties of the Pt/Ti-MOF-250 catalyst enable unique furfural (FAL) adsorption geometries, achieving exceptional FAL conversion (97.4 %) and high selectivity (98.1 %) toward furfuryl alcohol (FOL). The partial deligandation approach paves the way to enhance the physicochemical properties of pristine MOFs, enabling the homogeneous confinement and stabilization of Pt nanoparticle catalysts to achieve exceptional catalytic activity, selectivity, and stability in hydrogenation reactions.