Facile Synthesis of Polyaniline-Supported Pd Nanoparticles and Their Catalytic Properties toward Selective Hydrogenation of Alkynes and Cinnamaldehyde

Abstract

We report a facile method toward preparation of conducting polymer-supported Pd nanoparticles by in situ reducing the palladium salt [Pd(NO3)2] on the surface of polyaniline (PANI) film/membrane. The palladium(0) particles distribute evenly on the PANI surfaces. The size and morphology of Pd particles are dependent on the nature of the substrate surfaces. The palladium (Pd) particles on the PANI membrane surfaces have a rough surface morphology with a size distribution of ∼200 nm, and the Pd particles on the PANI film have a smooth surface with a size distribution of ∼500 nm. These Pd particles are in fact conglomerates of much smaller nanoparticles with an average size distribution of 13 nm. Pd nanoparticles exhibit efficient catalytic activity toward hydrogenation of alkynes and cinnamaldehyde with high selectivities dominated by a kinetic mechanism. Moreover, our results suggest that the variation in particle morphology resulting from substrates leads to differences in their catalytic efficiency presumably due to the difference in surface area. The PANI-supported Pd nanoparticles are robust and can be reused at least seven times without the significant loss of its catalytic activity and selectivity.