Sol–gel derived silver doped nanocrystalline titania catalysed photodegradation of methylene blue from aqueous solution

Nanocrstalline pure anatase titania doped with silver was prepared by sol–gel process at room temperature followed by ultrasonication (Ti–Ag–US). The photocatalytic activity of Ti–Ag–US has been evaluated by the degradation of textile dye, methylene blue in presence and absence of common inorganic salts (nitrate, acetate and sulphate). It was observed that in presence of anions the degradation of the dye increases significantly. The influence of the presence of H2O2 on the degradation rate was studied. The dependence of photodegradation of the dye rates on various parameters such as dye concentration, photocatalyst concentration and pH were also investigated. The photodegradation rate follows pseudo first order kinetics. H2O2 and UV light have a negligible effect in absence of Ti–Ag–US catalyst. The relative photonic efficiency of the system is reported using phenol as a standard organic compound.