*2.2.2 Synthesis of M/TiO2 (M = Ag, Au and Pt)*

The M/TiO2 (M = Ag, Au and Pt) catalysts were prepared by photoreduction method [9]. Calculated amounts of noble metal precursors (0.14 g of AgNO3 for 1% Ag/TiO2, 0.15 g of AuCl3 for 1% Au/TiO2, 0.14 g of [Pt(NH3)4]Cl2 for 1% Pt/TiO2) taken in minimum amount of water was added to 10 g of synthesised TiO2 and was stirred at 70°C till the evaporation of the solvent. The colloidal solution was then irradiated with 125 W halogen lamp until complete reduction was observed visually by the formation of black precipitate for Ag/TiO2, Pt/TiO2 and purple coloured product for Au/TiO2.
