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 TiO 2 nanotube (NT) arrays assisted by acidified carbon nanotubes (CNTs). Au crystals were electro-stacked along the electric field lines that are perpendicular to the TiO 2 substrate, constructing beautiful shrubs on TiO 2 NT arrays. In this process, the acidified CNTs with rich electrons attract Au 3+ 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/TiO 2 NTs exhibited a more sensitive response in sensing highly toxic As 3+ than Au films due to the higher surface area and unique three-dimensional structures.