Ultrasonically Assisted Synthesis of 3D Hierarchical Silver Microstructures

In this paper, we report on a facile, environmentally friendly, and ultrasonically assisted route to synthesis of three-dimensional (3D) hierarchical silver microstructures. This is achieved without the use of any templates, surfactants, or polymers. By reducing [Ag(NH 3 ) 2 ] + with H 2 O 2 in an aqueous solution, 3D flowerlike silver microstructures (FSMs) are formed within a few minutes. It is found that the duration of sonication and the quantity of H 2 O 2 play important roles in the formation of the 3D FSMs. The addition of citrate as a protecting agent changes the morphology of the products into that of 3D cauliflower-like silver microstructures (CSMs). Due to their large surface areas, these 3D hierarchical silver microstructures may find use as substrates for surface-enhanced Raman scattering applications.