Carbon-Nanotube-Guiding Oriented Growth of Gold Shrubs on TiO2 Nanotube Arrays

Shape-controlled synthesis of gold nanoparticles is common, while the crystal growth of dendritic gold architectures is rare, especially the perpendicular growth of shrub-like gold crystals on substrate. Herein, a simple potential-static electrodeposition method was developed to fabricate shrub-like gold nanostructures on TiO2 nanotube (NT) arrays assisted by acidified carbon nanotubes (CNTs). Au crystals were electrostacked along the electric field lines that are perpendicular to the TiO2 substrate, constructing beautiful shrubs on TiO2 NT arrays. In this process, the acidified CNTs with rich electrons attract Au3+ through electric attraction and work as primers guiding the Au growth along the direction of the electric field. The Au shrubs are single crystalline with intertwined symmetrical nanostructures. The as-prepared Au shrub/TiO2 NTs exhibited a more sensitive response in sensing highly toxic As3+ than Au films due to the higher surface area and unique three-dimensional structures.