Synthesis and visible light photoactivity of anatase Ag and garlic loaded TiO2 nanocrystalline catalyst

Abstract

An excellent visible light activated Ag and garlic loaded TiO₂ nanocatalyst was prepared by using AgNO₃ and garlic (Allium sativum) as the Ag⁺ and sulfur sources, respectively. The catalyst resisted the change from anatase to rutile phase even at high (700 °C) calcination temperature. The photocatalytic efficiency of as-prepared nanocatalysts was evaluated by degrading (100 ppm) azodye, methyl orange (MO), and dichloro phenol (DCP) under visible light irradiation for 3 to 4 h from an incandescent light bulb (300 W). The process followed first order reaction kinetics with reaction rates ranging from 9.5 × 10⁻⁴ to 19.4 × 10⁻³ min⁻¹. The dye was decomposed in 3 h and more than 70% DCP degraded in 4 h in the presence of Ag and garlic loaded–TiO₂ calcined at 700 °C. Demineralization of the solution was in the range 40 to 90%. A complete elimination of Vibrio fischeri was accomplished with 1 mg L⁻¹ of nanocatalyst regardless the calcination temperature. The catalyst was used for up to 5 consecutive runs without the significant loss in the photocatalytic activity and could be regenerated by adopting a simple procedure of washing with water and acetone as well as drying at 200 °C for 2 h.