Ag/Pt-modified TiO2 nanoparticles for toluene photooxidation in the gas phase

Ag/Pt-modified TiO2 nanocomposites were synthesized using the sol-gel method. The effect of metal type and amount as well as synthesis route on the photocatalytic activity in reaction of toluene removal, used as a model volatile organic compound, was investigated. Toluene, at the concentration of about 200 ppm, was irradiated over modified TiO2 using light-emitting diodes (LEDs, lambda(max) = 415 nm). The results showed that toluene could be mostly removed from the air after 20 min of irradiation over TiO2 modified with Ag/Pt bimetallic nanoparticles. The efficiency of toluene degradation in four subsequent cycles decreased from 99 to 53%, but it could be re-established by thermal treating of the sample. The photocatalyst showing the highest degradation rate consisted of large crystallites of Ag with a diameter of about 15-30 nm with fine Pt nanoparticles ranging from 0.8 to 2.0 nm surrounding TiO2 layer. (c) 2013 Elsevier B.V. All rights reserved.