Synthesis, characterization and computational study of nitrogen-doped CeO2 nanoparticles with visible-light activity.

Nitrogen-doped CeO2 nanoparticles were synthesized through a wet-chemical route. Nitrogen has been successfully incorporated into CeO2 nanoparticles and the nitrogen-doping level was also successfully controlled. The optical properties due to the different N-doping levels in CeO2 nanoparticles were characterized by UV-Vis diffuse reflectance spectroscopy (DRS), which showed a visible-light absorbance shift. The resulting nanoparticles show enhanced visible-light sensitivity and photocatalytic activity compared to undoped CeO2 nanoparticles. DFT calculations were performed to explore the effect of nitrogen doping versus oxygen vacancies. The calculations show that the change of the electronic structure upon N-doping CeO2 is quite different from that of N-doped TiO2, which has been studied extensively.