Quantitative generation of ROS and their effective photocatalytic antibacterial activity of high-intensity universal P25 network films: The role of ROS

Reactive oxygen species (ROS) generation and utilization were the foundation for the photocatalytic degradation of pollutants or anti-bactericidal effect. Especially for solid-phase film photocatalysis, a simple and firm immobilization method that ensured exposure of active sites and effective production of ROS was the key. Presently, a P25 network films was achieved using water-based polyurethane acrylate (WPUA) as adhesive through a simple and convenient direct spraying method. The physical and chemical properties of the P25 network films were characterized and the results showed that P25 was firmly adhered on the metal wire mesh and fully exposed the active sites of P25. Dynamic generation of ROS on 304SS@P25 films interface was systematically investigated. The concentration of hydroxyl radicals (•OH), superoxide radicals (O2•−) and hydrogen peroxide (H2O2) on 10 cm × 3 cm 304SS@P25 after 2 h of UV irradiation were 9.4 ± 0.3 × 10−9 M, 7.6 ± 0.3 × 10−9 M, and 11.7 ± 0.9 × 10−6 M, respectively, which was similar with ROS generation of P25 nanoparticle suspensions. In addition, the ROS-mediated antibacterial effect of 304SS@P25 films was investigated, and a linear correlation was found between the concentration of ROS generated and the E. coli sterilization rate. Furthermore, 304SS@P25 films could be successfully applied in the air sterilizer to exhibit a good bactericidal effect. This ROS-oriented photocatalyst immobilization method opened up a new pathway for water and air purification and provided a new strategy in the field of photocatalytic antibacterial technology.