Selective growth of TiO2 beads on Ag nanowires and their photocatalytic performance

Abstract

In this paper, TiO₂ beads were deposited on Ag nanowires to create necklace-like Ag nanowire@TiO₂ (Ag NW@TiO₂) heterostructures for the first time. They were fabricated via a two-step synthetic method, including the preparation of uniform Ag NWs and the deposition of TiO₂ on the Ag surface. Thioglycolic acid (TGA) molecules were used as binding agents to solve the tricky issue of substantial lattice mismatch between the Ag NW core and the TiO₂ shell. The amount of water and the permittivity of the solvents are found to be important factors for the formation of the necklace-like heterostructures. Moreover, by varying the amount of titanium butoxide (TBT), the diameter of the TiO₂ beads can be feasibly changed. The photocatalytic performance of necklace-like Ag NW@TiO₂ was evaluated via degradation of methyl orange (MO) under ultraviolet (UV) light. The results reveal that the molar ratio of TiO₂ to Ag contributes to the synergistic effect on the photocatalytic activity, and the best Ti/Ag ratio is found to be 2.8 for the highest photocatalytic performance of the Ag NW@TiO₂ heterostructures.