Well-Dispersed Water-Soluble Pd Nanocrystals: Facile Reducing Synthesis and Application in Catalyzing Organic Reactions in Aqueous Media

Abstract

A facile one-step aqueous reducing synthetic method has been reported for the preparation of noble metal nanocrystals (or colloid) of palladium through the reduction of in situ generated aldehyde ammonia from the hydrolyzation of hexamethylenetetramine with the help of sodium oleate in water under mild conditions. The as-obtained nanocrystals were monodispersed in water with narrow size distribution, and their mean size could be tuned from 3 to 8 nm rationally. The developed synthetic route has been extended to other noble metals including Au, Ag, and Pt and bimetallic Pd−Pt nanocrystals. Meanwhile, the catalytic activities of the Pd nanocrystals were tested in aqueous media, and typically dechlorination of aryl chloride and Suzuki cross-coupling reaction are selected as model reactions. Investigations demonstrated that the Pd nanocrystals have good catalytic performance since both dehalogenation and cross-coupling reaction have high yields under current mild conditions. The results suggest that the Pd na...