Solar light active biogenic titanium dioxide embedded silver oxide (AgO/Ag2O@TiO2) nanocomposite structures for dye degradation by photocatalysis

A novel method of synthesis of TiO 2 embedded AgO/Ag 2 O nanocomposite using the cell free culture supernatant of the bacteria Alcaligenes aquatilis at room temperature is reported. Highly crystalline nanocomposite containing rutile TiO 2 , Ag 2 O and AgO was formed by the biosynthesis route. AgO/Ag 2 O particles were embedded in TiO 2 and the average particle size was found to be 13.4 nm. The synthesized nanocomposite with a band gap energy of 1.75 eV was found to degrade 100 ppm Reactive Blue 220 dye almost completely in acidic pH at a catalyst loading of 1 g/L under visible light irradiation in 90 min. The nanocomposites also showed good photocatalytic activity under solar light, and thus can be used effectively in solar driven photocatalysis for waste water treatment. • TiO 2 embedded Ag 2 O/AgO–TiO 2 nanocomposite synthesized using Alcaligenes aquatilis . • AgNO 3 reduction is followed by TiO 2 formation by the cell free supernatant. • The nanocomposite formed has particle size of 13.4 nm and band gap of 1.75 eV. • Complete degradation of Reactive blue-220 dye under visible light. • The nanocomposite is an efficient visible and solar light active photocatalyst.