Facile synthesis of magnetic recyclable palladium-gold alloy nanoclusters catalysts PdAur/Fe3O4@LDH and its catalytic applications in Heck reaction

Abstract

A series of novel magnetic recyclable PdAu nanoclusters (NCs) catalysts x-PdAur/Fe3O4@LDH (x: Pd loading in wt%, r: Au/Pd molar ratio, LDH: layered double hydroxide, here refers the typical MgAl-LDH) were synthesized by a facile polyol reduction followed sol immobilization of PdAur–PVP on core@shell support Fe3O4@LDH. Systematic characterizations reveal that the obtained catalysts possess the honeycomb-like core@shell, and the ultrafine PdAu alloy nanoclusters with the size in 1.70–2.55 nm highly dispersed on the LDH nanoplates shell. The obtained catalysts 1.0-PdAur/Fe3O4@LDH (r: 0.11, 0.16 and 0.48) show higher Heck activity of iodobenzene with styrene than monomentallic ones, especially 1.0-PdAu0.16/Fe3O4@LDH displays the highest Heck activity under the optimal condition. Moreover, the catalysts can be applied for the Heck reaction of a variety of aryl halides with alkenes, and can be conveniently separated by an external magnet and reused ten runs without significant loss of activity.