ABSTRACT
Superoxide radical ( O·-2 ) , is one of reactive oxygen species ( ROS ) produced in TiO2 photocatalytic reactions, and plays an important role in the photodegradation of pollutants. In this work, we constructed two different procedures to study the generation of total O·-2 and surface-adsorbed O·-2 during TiO2 photocatalytic reaction using nitroblue tetrazolium ( NBT) as capture probe. Furthermore, three different TiO2 ( anatase, rutile and P25 ) were selected as model, and O·-2 generation and its existence form were all studied. The results showed that the generation of total O·-2 was followed by the order P25> anatase> rutile, but the surface-adsorbed O·-2 was nearly the same. The study of surface-adsorbed ROS is very important due to their probably persistence for the pollutants photodegradation or antibacterial activity.