Ultrafast Preparation of Three-Dimensional Dendritic Gold Nanostructures in Aqueous Solution and Their Applications in Catalysis and SERS

Three-dimensional dendritic gold nanostructures were prepared via an ultrafast one-step homogeneous solution method. Cationic surfactants, decane-1,10-bis(methylpyrrolidinium bromide) ([mpy-C-10-mpy]Br-2), were used as the capping agent and L-ascorbic acid (AA) was used as the reducing agent. The as-prepared gold dendrites present a [111] plane and grow along the (211) direction. The AA plays an important role in the formation of the dendritic nanostructures. The methylpyrrolidinium quaternary ammonium headgroups and bolaform nanostructures of the surfactants are the key factors for the formation of dendritic structures. Further investigation revealed that the reaction time and concentration of HAuCl4 weakly affect the formation of the dendrites. Moreover, the obtained gold dendrites exhibit excellent activity toward the catalytic reduction of p-nitraniline and higher enhancement of surface-enhanced Raman scattering when using Rhodamine 6G as the model molecules.