Nature of Ag-Bi-codoped TiO2 visible light photocatalyst

Surface modification of titanium dioxide (TiO 2 ) with silver and bismuth was performed to increase the photocatalytic degradation of methylene blue (MB). The effect of initial calcination temperature, reaction time, catalyst loading and initial pH value was studied. The physicochemical properties of as-prepared samples were characterized by XRD, UV-Vis DRS, TG-DTG and XPS. The results indicate that Ag-Bi-TiO 2 has more excellent visible light photocatalytic activity in degradation of MB than that of pure TiO 2 photocatalyst. The optimum synthesis condition is justified at the Ag/Bi ratio as 1, the calcined temperature as 350 °C, the catalyst amount as 1.25 g/L and the pH value of solution as 5.98. Decolourizing rate of solution rises to 95 % within 5 h and the mineralization ratio of 24 h to 85.1 %. The codoped metals exist in manifold oxide forms in Ag-Bi-TiO 2 sample. Namely, they can extend the photoresponsiveness into the visible light region, thus showing the potential applications for the degradation of organic pollutants.