The Synthesis of Eu3+ Doped with TiO2 Nano-Powder and Application as a Pesticide Sensor

Using tetrabutyl titanate as precursor, Eu3+ doped TiO2 nano-powder was prepared by sol-gel method, the nature of luminescence of nano-powder was studied. The interaction of chlorpyrifos with Eu3+ doped TiO2 was studied by absorption and fluorescence spectroscopy. The results indicated the fluorescence intensity of Eu3+ doped TiO2 was quenched by chlorpyrifos and the quenching rate constant (kq) was 1.24x1011 L/mol s according to the Stern-Volmer equation. The dynamics of photoinduced electron transfer from chlorpyrifos to conduction band of TiO2 nanoparticle was observed and the mechanism of electron transfer had been confirmed by the calculation of free energy change (Delta Get) by applying Rehm-Weller equation as well as energy level diagram. A new rapid method for detection of chlorpyrifos was established according to the fluorescence intensity of Eu3+ doped TiO2 was proportional to chlorpyrifos concentration. The range of detection was 5.0x10(-10) - 2.5x10(-7) mol/L and the detection limit (3s) was 3.2x10(-11) mol/L.