ИСТИНА

We have studied nitrogen doped TiO2 nanocrystals, TiO2 based nanoheterostructures (TiO2/MoO3, TiO2/WO3, TiO2/V2O5, TiO2/MoO3/V2O5) and microspheres (TiO2/MoO3, TiO2/WO3, TiO2/V2O5, TiO2/MoO3/V2O5, TiO2/WO3/V2O5, TiO2/MoO3/WO3, TiO2/MoO3/V2O5/WO3) using our new approach. We have studied initial samples and ones with test dye. Dye Rhodamine 6G in an amount of 4×10–8 mol/cm2 was applied to the surface of the TiO2 based photocatalyst from an aqueous solution. All EPR experiments were made both in dark and under illumination. The dynamics of radicals was studied under visible illumination both in the initial samples and in the photocatalysts with Rhodamine 6G. N•, Ti3+; Mo5+,V4+, O-, O2- paramagnetic centers were found in the initial samples in dark. The concentration of N•, Ti3+; Mo5+,V4+ centers increases under illumination which can be explained by the capture of photoexcited charge carriers by initially non-paramagnetic centers. It was revealed that the concentration of O-, O2- radicals decreases under illumination in the samples with Rhodamine 6G. This result indicates their consumption in the process of redox reactions on the surface of the samples. After the illumination is switched off, the con-centration of revealed paramagnetic centers returned to its original state for a very long time (approximately within 50 hours).Therefore we have detected the effect of separation and ac-cumulation of photoexcited electrons and holes in TiO2 based nanoheterostructures.