Facile Synthesis of Au/Pd Nano-dumbells for Catalytic Reduction of p-Nitrophenol

Au nanorods (Au NRs) with good monodispersity and uniform aspect ratio were prepared via seed-meditated method. Au/Pd nano-dumbbells (Au/Pd NDs) were synthesized by using H2PdCl4\ as precursor, hexadecyl trimethyl ammonium chloride (CTAC) as soft template, Ag+ as structure-directing agent and ascorbic acid as reduction agent to modify Au NRs. Structure and morphology of the samples were characterized by transmission electron microscope (TEM), energy dispersive spectrometer (EDS) and ultraviolet-visible-near infrared spectrophotometry (UV-Vis-NIR). The formation mechanism of Au/Pd NDs were discussed. The results of Au/Pd NDs samples demonstrated that lots of poly-crystalline Pd particles were deposited onto two ends of Au nanorods selectively to form dumbbell-like structure. The dumbbell size can be continuously tuned by adjusting the molar ratio of AA and H2PdCl4. The experiments of reduction of p-nitrophenol by NaBH4 to p-aminophenol indicate that the sample with good dispersibility and large number of total catalytic active sites of Pd nanoparticles has high catalytic performance. Adding 0.04 mg/mL Au/Pd NDs with suitable Pd particles size (20.7 nm) show excellent catalytic activity (rate constant 0.44 min(-1)), indicating it is useful for reducing p-nitrophenol.