Metal negative-ion implantation into rutile TiO₂ and enhancement of photocatalytic property under irradiation of fluorescent light

Optical absorption and photocatalytic properties of metal negative-ion implanted rutile TiO₂ were studied to show metal nanoparticle formation in the surface region and improvement of photocatalytic efficiency. Silver negative ions were implanted into titania substrate (rutile crystalline substrate) at 65 keV with a dose of 3 × 10¹⁶ - 1 × 10¹⁷ ions/cm². The Ag-implanted rutile also showed a strong optical absorption appeared near 2.1 eV after annealing above 400°C, those well agreed with theoretical absorption peaks due to surface plasmon resonance. This means that Ag nanoparticles were formed in the surface layers of the rutile TiO₂. Photocatalytic efficiencies for Ag-implanted titania of were evaluated by means of decolorization of methylene blue solution under fluorescent light. Ag-implanted rutile TiO₂ (Ag: 65 keV, 5 × 10¹⁶ ions/cm², 500°C annealed) showed the better photocatalytic efficiency higher 2.2 times than that of unimplanted rutile TiO₂. In the evaluation under fluorescent light through UV-cut filter for 19 h, the Ag-implanted rutile showed 6.7 times better efficiency.