Synthesis, characterization, and visible light activity of new nanoparticle photocatalysts based on silver, carbon, and sulfur-doped TiO2.

New nanoparticle photocatalysts based on silver, carbon, and sulfur-doped TiO2 having only the homogeneous anatase crystalline phase and high surface area were successfully synthesized by a modified sol-gel route. The catalysts were characterized by EDX, XRD, BET, UV-vis, IR, and Raman spectroscopy. The effects of the experimental parameters on the visible light reactivity of the catalysts were evaluated for the photodegradation of gaseous acetaldehyde as a model indoor pollutant. The activity results show that the silver(I) ion, Ag(+), doping significantly promotes the visible light reactivities of carbon and sulfur-doped TiO2 catalysts without any phase transformation from anatase to rutile. Moreover, Ag/(C, S)-TiO2 photocatalysts degrade acetaldehyde 10 times faster in visible light and 3 times faster in UV light illuminations than the accredited photocatalyst P25-TiO2. The commendable visible photoactivities of Ag/(C, S)-TiO2 new nanoparticle photocatalysts are predominantly attributable to an improvement in anatase crystallinity, high surface area, low band gap and nature of precursor materials used.