| Graphene, a two dimensional sheet of hexagonally arrayed carbon atoms, hasattracted intensive attentions because of the unique chemical and physical properties.With large surface areas, unique electronic properties, impressive mechanical strengthand no microporosity, graphene has been widely considered as a new support to loadAu, Pd, Ag, and Pt monometallic nanoparticles, which showed impressive catalyticperformance in various reactions. The as prepared composites were characterized byTransmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM),X-Ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), Energy X-raySpectroscopy and Electronic energy Loss Spectroscopy (EELLS). Besides, catalyticactivity of the composites was tested by different reactions, and we investigated theimpact of the particle size and the structure of the bimetallic nanoparticles on thecatalytic performance.The main results obtained are as follows,1. AucorePdshell(Au@Pd) bimetallic nanoparticles of sub-10nm were successfullydispersed on graphene by a simple one step reducing method (Ascorbic Acid wasused as reducer, and Citrate was used as surfactant). Characterization results showedthat Au@Pd bimetallic nanoparticles were well dispersed on the surface of graphenewith an average size of7.4nm. EELLS spectrum confirmed the core-shell of the asprepared Au@Pd bimetallic nanoparticles. Besides, Evaluation of their catalyticperformance demonstrates the Au@Pd–G hybrids have extraordinary peroxidaseactivity as catalysts.2. Graphene supported Ag Au alloy nanoparticles with diameters of sub-7nm wereprepared by a simple and prompt microwave assisted one-step method. TheTEM-EDS and compositional line profiles further confirmed the alloy prosperity ofthe as prepared nanoparticles on the surface of graphene. These structures exhibitedsignificantly enhanced catalytic activity compared with monometallic counterparts inthe reduction of4-nitrophenol (4-NP) by sodium borohydride (NaBH4). |
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