A novel method for detecting . OH radicals generated by photoexcited nanoparticles

The Fenton reactions occur because of the generation of H2O2 in the photoex cited independent TiO2 systems or TiO2/SnO2 coupled systems. The . OH radic als in these reactions were indirectly measured by colorimetric method. Acc ording to the Lambert-Beer law, we obtained the qualitative and quantitativ e relationships between the amount of TiO2 or TiO2/SnO2 coupled particles a nd the amount of . OH radicals produced by these systems. It provides a con venient procedure for making a thorough study on the photocatalytic mechani sm of semiconductor nanoparticles, and in particular, to select highly effi cient multicomponent semiconductor systems for photocatalysis. (C) 1998 Els evier Science Limited. All rights reserved.