Effect of Formation of Ag2Ti4O9 Phase on Photocatalytic Activity of Ag-TiO2 Nanocomposite

Ag-TiO2 nanocomposite with the optimum concentration of 1wt% was produced by a sol-gel process using Rhodamine B for the catalytic activity. The initial samples were prepared by heat treatment at various temperatures (266, 338, 390, 485, 600 and 700°C) with a holding time of 2 h. DTA and XRD of these samples led to choosing the temperature of 530°C as the heat treatment temperature. Then some samples were heat treated at this temperature for various times (0.5, 1, 2, 4, and 6 h). The samples heat treated for 2 h at 266 and 338°C exhibited better degradation efficiency. The 530°C-1 hr sample exhibited the best degradation performance even in comparison with the commercial nano TiO2 purchased from Degussa. To the best of our knowledge, we report (for the first time) the formation of Ag2Ti4O9 phase at ambient temperature. This silver titanate phase gives rise to a better degradation efficiency compared to anatase. Characterization of Ag-TiO2 samples was done by DTA, XRD, PL and SEM.