Hydrothermal growth of nanorod arrays and in situ conversion to nanotube arrays for highly efficient Ag-sensitized photocatalyst

TiO 2 nanorod arrays (NRAs) were hydrothermally grown on transparent fluorine-doped tin oxide (FTO) substrates, and were converted into nanotubes (NTAs) by hydrothermally in situ etching. Ag nanoparticles (NPLs) were sensitized on the NRAs and NTAs by a simple photodeposition approach (products were denoted as Ag-TiO 2 NRAs and NTAs). The Ag-TiO 2 NTAs samples possessed a large specific surface area (116 m 2  g -1 ) with Ag NPLs homogeneously dispersed among the TiO 2 NTAs. The Ag-TiO 2 NTAs exhibited significantly enhanced photocatalytic activities (98.8%) in degradation of methyl orange (MO) compared to Ag-TiO 2 NRAs (92.6%), TiO 2 NTAs (86.2%), and NRAs (81.7%). The enhanced photocatalytic activities can be attributed to the large specific surface area of TiO 2 NTAs and strong surface plasmon resonance (SPR) of Ag NPLs. In addition, Ag-TiO 2 NTAs showed easy recovery feature in the recovery process and high durability in the recycling test, which was expected to be an efficient and practical photocatalyst used for waste water treatment.