Bimetallic Fe_xPt_100–x Nanoparticles Immobilized on Supported Ionic Liquid Phases as Hydrogenation and Hydrodeoxygenation Catalysts: Influence of the Metal Content on Activity and Selectivity

Iron–platinum nanoparticles of tunable Fe/Pt ratios were immobilized on an imidazolium-based supported ionic liquid phase (SILP). The resulting Fe x Pt 100– x @SILP materials were characterized and applied in catalysis. Electron microscopy confirmed the formation of small, well-dispersed, bimetallic nanoparticles in all the investigated materials. Magnetometry measurements evidenced a clear influence of the Fe/Pt ratio on the oxidation state of Fe in Fe x Pt 100– x @SILP. In particular, Fe appeared in the metallic state at x ≤ 40, whereas partial oxidation was observed at x ≥ 60. The catalytic properties of Fe x Pt 100– x @SILP materials were probed using the reduction of benzylic ketones with H 2 as a model reaction. The Fe/Pt ratio of the nanoparticles was found to have a critical influence on the observed activity and selectivity, with clear synergistic effects. In particular, by diluting Pt with Fe sites, the ability of Fe x Pt 100– x @SILP catalysts to hydrogenate 6-membered aromatic rings was shut down for x ≥ 40, while C═O hydrogenation activity was preserved. In addition, Fe 40 Pt 60 @SILP showed excellent hydrodeoxygenation activity and selectivity with acetophenone derivatives in the absence of acid additives. This remarkable reactivity, out of reach for monometallic Pt@SILP, is attributed to the enhanced oxophilicity of Fe in FePt catalysts favoring C═O activation and cleavage.