The Preparation Of Graphene Supported Pt/Ni Bimetallic Alloy Nanoparticles And Its Application As Magnetically Separable Nanocatalysts

Graphene, a one-atom thick planar sheet of hexagonally arrayed sp2carbonatoms, has attracted tremendous attention in recent years. It was discovered by AndreGeim and Konstantin Novoselov in2004. Graphene has demonstrated the existence oftwo dimensional nanomaterials. Given its two-dimensional structure and uniqueproperties, graphene is a promising candidate in many technological fields, such asnanoelectronics, sensors, supercapacitors, hydrogen storage, etc. Especially, graphenehas been emerging as a promising supporting in heterogeneous catalytic processes.In recent years, many monometallic and bimetallic catalytic nanoparticles havebeen utilized in heterogeneous catalytic processes, and the introduction of grapheneinto metal clusters can prevent nanoparticles from aggregating due to its large surfaceareas, impressive mechanical strength and chemical inertness. However the efficientrecovery of nanocatalyts, especially the graphene supported noble metal catalystsremains a challenge. In this study, we report a simple one step route to prepare thegraphene supported Pt/Ni nanocatalyst with ideal superparamagnetic properties.The main results obtained are as follows:(1) Pt/Ni bimetallic nanoparticles were successfully dispersed on graphene by asimple one step reducing method, N2H4·H2O as reducer and Tannin as surfactant. Thewhole preparation cost about one hour and the reducing procedure only need15mins.The as prepared composites were characterized by Transmission Electron Microscopy(TEM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), X-RayPhotoelectron Spectroscopy (XPS), Raman, etc.(2) The graphene supported Pt/Ni hybrids (Pt/Ni–G) were demonstrated toshow excellent catalytic activities in the catalytic reduction of aromatic nitrocompounds (p-nitrophenol). The optimal Pt/Ni–G nanocatalysts were acquired by thecomparison of catalytic activities using different concentration of Pt/Ni–G. Thehighest reaction rate constant (k) could be1.476min–1. And the magneticallyseparable nanoparticles could be easily separated from the reaction mixtures byapplying an external magnetic field, resulting in favorable reusability.