The effect of X-ray induced oxygen defects on the photocatalytic properties of titanium dioxide nanoparticles

The effect of X-ray irradiation on titanium dioxide (TiO2) nanoparticles and their photocatalytic activity was studied through surface chemistry analysis after irradiation and TiO2 degradation of methylene blue (MB). Detailed X-ray photoelectron spectroscopy (XPS) analysis showed that an increased number of oxygen vacancies, chemisorbed oxygen, and OH groups were formed at the surface of the nanomaterial with increasing irradiation dose. Moreover, the formation of these features in the structure and surface of TiO2 showed an improved catalytic activity. The superior performance of the catalyst upon X-ray irradiation is caused by the introduction of new energy levels below the conduction band of the catalyst, which generates trap centers that delay the recombination rate of electron-holes pairs. Degradation of MB in the presence of TiO2 showed reaction rate coefficient enhancements of- 47.6 %-61.6 % when TiO2 with a mean size of 6.5 nm was irradiated at doses of 10 and 60 kGy respectively. Overall, our experiments showed promise of the X-ray irradiation as a feasible surface treatment that showed significant improvements in the photocatalysis of TiO2.