title: Functionalization of platinum nanoparticles with L-proline: simultaneous enhancements of catalytic activity and selectivity.
abstract: In this work we present the successful application of functionalizing Pt nanoparticles (NPs) with hydrophilic organic ligands as a strategy for enhancing their catalytic activity and selectivity. In the first step, Pt NPs were prepared by a colloidal approach and subsequently functionalized in a separate synthesis step with L-proline (PRO). The functionalized NPs were supported onto Al2O3 and investigated as heterogeneous catalysts for the selective hydrogenation of acetophenone. Whereas significant amounts of side products are formed by supported, "unprotected" (ligand-free) NPs, the PRO-functionalized Pt NPs are highly chemoselective even at 100% conversion. Experiments under kinetically controlled conditions reveal that this high chemoselectivity is not accompanied by a loss of catalytic activity. In contrast, an enhanced rate toward the desired product was found for PRO-Pt in comparison to the "unprotected" Pt NPs. This finding demonstrates that the use of ligands in heterogeneous catalysis allows for simultaneous enhancements of activity and selectivity.
authors.affiliation: Institute for Applied and Physical Chemistry and ‡Institute for Organic and Analytical Chemistry, University of Bremen , Leobenerstraße, 28359 Bremen, Germany.
authors.forename: Imke
authors.initials: I
authors.lastname: Schrader
authors.forename: Jonas
authors.initials: J
authors.lastname: Warneke
authors.forename: Jana
authors.initials: J
authors.lastname: Backenköhler
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kunz
mesh_terms: D000098:Acetophenones / Q000737:chemistry; D002384:Catalysis; D003510:Cyclohexanes / Q000737:chemistry; D006865:Hydrogenation; D053768:Metal Nanoparticles / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010984:Platinum / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*; D013379:Substrate Specificity
chemical_list: D000098:Acetophenones; D003510:Cyclohexanes; C506365:Cyclohexane; D010984:Platinum; D011392:Proline; C038699:acetophenone