Pd/PdO nanoparticles supported on carbon nanotubes: A highly effective catalyst for promoting Suzuki reaction in water

We report that the presence of PdO nanoparticles can enhance the catalytic performance of Pd catalyst for the Suzuki reaction in water. Heterogeneous Pd/PdO nanoparticles supported on multi-walled carbon nanotubes (CNTs), weakly oxidized multi-walled carbon nanotubes (WCNTs) and strongly oxidized multi-walled carbon nanotubes (SCNTs) catalysts are synthesized by a one-pot gas-liquid interfacial plasma (GLIP) method using Pd(NO3)(2)center dot 2H(2)O as precursor. Among these synthesized catalysts, the Pd/PdO supported on WCNTs (Pd/PdO/WCNTs) catalyst exhibits the highest catalytic activity during the Suzuki reaction in water. Moreover, the Pd/PdO catalyst shows higher catalytic activity during the Suzuki reaction than Pd catalyst. The as-prepared catalyst displayed remarkable activity toward challenging substrates such as heteroaryl halides and ortho-substituted aryl halides as well as aryl chlorides using low Pd loading in good yields. Since the catalyst exhibits extremely low solubility in organic solvent, the product can be simply extracted with ethyl acetate while the catalyst remained in the aqueous phase. The catalyst can be simply and efficiently used for ten consecutive runs without significant decrease in activity. (C) 2015 Elsevier B.V. All rights reserved.