Catalytically active network-like gold nanostructures:Synthesis and study of growth mechanism

Generation of network-like Au nanostructures by the reduction of gold ions in aqueous solution by bismuth ammonium citrate at room temperature is reported. The as-synthesized Au nanostructures have been characterized by spectroscopic, microscopic and diffractometric techniques. Microscopic results confirm that variation of HAuCl4 concentration in the reaction mixture results in the formation of different types of network-like Au nanostructures. Kinetic results indicate that these network-like Au nanostructures are formed by the oriented attachment based self-assembly of smaller sized spherical Au nanoparticles. X-ray diffraction studies reveal that the formed Au nanostructures are crystalline. These network-like Au nanostructures are catalytically active and can be used to catalyze both the reduction of p-nitrophenol and redox reaction between K3[Fe(CN)6] and Na2S2O3. Further, these network-like Au nanostructures are reusable in both types of reactions without much loss in their catalytic activity.