Self cleaning of hazardous organic materials by TiO2 nanoparticles derivatives

Avraham Dayan, The School of Molecular Cell Biology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel (avi_idf@hotmail.com)
Gideon Fleminger, The School Of Molecular Cell Biology And Biotechnology, George S. Wise Faculty Of Life Sciences, Tel Aviv University, Tel Aviv, Israel

The photocatalytic activity of titanium dioxide (TiO₂) due to the generation of reactive oxygen species (ROS) under UV-excitation is often used for the decontamination of toxic hazardous materials and self-cleaning processes. However, the large band-gap of TiO₂ limits the activity to the UV region. This limitation can be overcome by metal doping, which results in extending TiO₂ activity into the visible range (VIS). This paper describes the preparation and characterization of several TiO₂ forms and their modifications for enhanced photocatalytic activity at the UV-VIS range. In order to advance this concept for environmental decontamination, the degradation of the phosphorous-organic pesticide and chemical warfare agent, profenofos (PF), was tested. Fast and full degradation of PF was achieved using either TiO₂ at the near UV (365 nm) or Ag-doped TiO₂ (TiO₂-Ag) at the UV and VIS ranges (400-550nm). The degradation products were identified chromatographically using GC/MS and HPLC, while the detoxification effect was determined electrochemically using an acetylcholinesterase biosensor. In view of our results we suggest that TiO₂-Ag may be implemented as an additive in surface coatings to allow in situ green self-cleaning.