Enhanced photo--catalytic activity of gold ion and gold modified

The gold ion modified TiO 2 was prepared by means of sol|gel whereas gold deposited TiO-2 was prepared by means of photo|reduction. The physical properties were influenced significantly by the presence of gold ion or gold. The enhanced photo|activity of gold modified TiO-2 was quantified in terms of methylene blue degradation. The presence of gold ion in TiO-2 lattices or gold on TiO-2 surface enhanced their photo|activity. The optimum molar content of gold ion doping and gold deposition all was 0.5%. The first|order rates constants of gold modified TiO-2 was more than that of pure TiO-2, and decreased by increasing the content of gold ion and gold when their contents were more than 0.5%. Gold ion doped in TiO-2 lattices was more effective to enhance the photo|activity than gold on TiO-2 surface. Moreover, the relationship between physical properties, chemical properties and photo|activity has been discussed.