AuPd bimetallic nanoparticles decorated on graphene nanosheets: their green synthesis, growth mechanism and high catalytic ability in 4-nitrophenol reduction

A one-pot green method to synthesize ultrafine AuPd nanoparticles (NPs) monodispersed on graphene nanosheets (GNs) is reported. Due to the reducing capability, moderate number of deposition sites and large surface area, GNs are used as a three-functional agent such as reductant, stabilizer and support in this synthesis. The morphology, structure and composition of thus-prepared AuPdNPs/GNs were characterized by transmission electron microscopy (TEM), high resolution TEM, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. As it is a surfactant-free formation process, the as-prepared AuPdNPs/GNs are very clean and can exhibit a high activity towards the reduction of 4-nitrophenol. Moreover, the optical properties and catalytic activities of the AuPdNPs/GNs composite are tunable via controlling the Au versus Pd atomic ratio during their synthesis. The catalytic activity of bimetallic AuPdNPs/GNs composites is highly enhanced over the monometallic AuNPs/GNs and PdNPs/GNs composites. This straightforward method is of significance for deposition of bimetallic NPs with high catalytic performance on graphene-based materials.