Synthesis and photocatalytic applications of Ag/TiO2-nanotubes

TiO₂- and Ag/TiO₂-nanotubes (NTs) were synthesized by hydrothermal methods and microwave-assisted preparation, respectively. Scanning electron microscopy, high resolution transmission electron microscopy, Brunauer-Emmett-Teller particle surface area measurement and X-ray diffraction were used to characterize the nanotubes. Rutile TiO₂-NTs with Na₂Ti₅O₁₁ crystallinity had a length range of 200-400 nm and diameters of 10-20 nm. TiO₂- and Ag/TiO₂-NTs with a 0.4% deposition of Ag had high surface areas of 270 and 169 m² g⁻¹, respectively. The evaluation of photocatalytic activity showed that Ag/TiO₂-NTs displayed higher photocatalytic activity than pure TiO₂-NTs and a 60.91% degradation of Rhodamine-B with 0.8% deposition of Ag species. Also 60% of Rhodamine-6G was physisorbed and 40% chemisorbed on the surface of TiO₂-NTs. In addition, the photocatalytic degradations of organochlorine pesticides taking α-hexachlorobenzene (BHC) and dicofol as typical examples, were compared using Ag/TiO₂-NTs, and found that their degradations rates were all higher than those obtained from commercial TiO₂.