Dumbbell-shaped polymeric nanoparticles with one-side anchored Pd-clusters for efficient catalytic hydrogenation at biphasic interfaces

Abstract

Pickering interfacial catalysts incorporated with amphiphilic architecture significantly expand the sustainability of green catalysis systems. In this work, we present precise and well-designed dumbbell-shaped Janus-structured polymeric nanoparticles with one-side anchored palladium clusters (DB-JPP-Pd) as Pickering interfacial catalyst for static hydrogenations. The large wettability difference of each lobe renders the prominent amphiphilicity of the dumbbell-shaped DB-JPP-Pd. The amphiphilic Janus catalyst displays excellent interfacial activity and extensively reduces the interfacial tension from 34.06 ± 0.13 to 20.54 ± 0.31 mN/m, promoting the formation of a more stable Pickering emulsion than that of the bulk PS-Pd catalyst, which can continuously provide a large interfacial area and shorten the molecular mass transfer distance during the reaction process. As a result, the DB-JPP-Pd catalyzed nitroarene reduction reaction exhibits a normalized reaction rate constant (knor) of 3.39 min−1⋅g−1⋅L under static conditions, which is 56.5 times higher than that of bulk PS-Pd. The constructed Pickering interfacial catalysis (PIC) system converts all the nitrobenzene into aniline within three minutes and possesses excellent selectivity in hydrogenations of different nitro aromatics. In addition, the emulsion catalytic system was conveniently recycled for ten consecutive runs. Hence, this unique amphiphilic dumbbell-shaped catalyst effectively develops an efficient static biphasic catalysis system.