Ag-Doped TiO2 nanotubes (TNTs) were fabricated with facile two-step anodization process. In addition, the catalytic activity of Ag-Doped TiO2 nanotubes was examined in photocatalytic degradation of 2,4-dicholorophenol. Characterizing of Ag-Doped TiO2 nanotubes were evaluated by FESEM, TEM, XRD, DRS and Spectrophotometry analyses. Results show that doping Ag nanoparticles uniformly distributed over the TNTs without any distraction in a tubular structure. Anatase crystalline phase was obtained by annealing the Ag-Doped TNTs at 550 °C. DRS results showed the addition of Ag nanoparticles had a sufficient effect of band gap which it decreased the band gap from 2.9 to 2.7. Pure TiO2 nanotubes showed 74% removal of 2,4-dicholorophenol. photocatalytic degradation study indicated that Ag-dopant has an efficient impact on photocatalytic activity of TNTs witch Ag-Doped TNTs could degrade 91% of 2,4-dicholorophenol under UV irradiation.

p-nitrophenol (PNP) is a nitroaromatic compound that poses a potential environmental hazard because of its acute toxicity, high carcinogenicity, low biodegradability and cumulative effect. Titanium dioxide (TiO2) nanotubes have shown great potential as ideal and powerful photocatalysts in purification of polluted water due to their high photo oxidation, anti-fogging, nontoxicity, good chemical stability and low cost. Therefore, TiO2 nanotube arrays were fabricated by two-step anodization process at 30,40 and 50V; and were used in photocatalytic degradation of organic pollution p-nitrophenol. In order to have the crystal structure, nanotubes were annealed at 450 °C for 2 hours. Characterizing of TiO2 nanotubes were evaluated by FESEM, XRD and Spectrophotometry analyses. Effect of anodization voltage on nanotube’s length and diameter were investigated. The result showed that as anodization voltage increases from 30V to 50V, nanotube’s length, diameter and wall thickness increase linearly from 1.4 μm to 4.8 μm, 45 nm to 100nm and 15nm to 25 nm, respectively. Increasing in anodization voltage lead to enhancement in porosity (0.4-0.5) and roughness factor (109-194) of TiO2 nanotubes, respectively. By investigating kinetic of degradation of p-nitrophenol, it was observed that mechanism of photocatalytic degradation for all samples are followed first order kinetic. The results indicate that amongst all synthesized samples, 50 V sample with 38%, shows the most efficiency in degradation of p-nitrophenol under UV irradiation.