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

Abstract

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 <em>p</em>-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.