Effect of Au position on the photoelectrochemical and photocatalytic activity of TiO₂ nanotubes under UV irradiation

Heterostructures have excellent physicochemical properties, which have attracted much attention in photoelectrochemical and photocatalytic fields. Au-TiO2NTs and Au@TiO2NTs were fabricated by the impregnation method and a vacuum-assisted-impregnation route, respectively. The effects of Au position on the structural and photoelectrochemical properties and photocatalytic activity of TiO2 have been characterized and studied. The Au@TiO2NTs photoelectrode showed a significant photocurrent (∼17 μA/cm2), which was approximately 8.5 and approximately 2.3 times greater than that of TiO2NTs and Au-TiO2NTs. Meanwhile, Au@TiO2NTs also exhibited the best photocatalytic activity and stability for tetracyclines degradation. The characterization and experimental results revealed that the better performance of Au@TiO2NTs may be attributed to the smaller Au nanoparticles inside the nanotube space, the reduced interfacial charge transfer resistance, and the stronger electronic interaction between Au nanoparticles and TiO2NTs.