Visible-light-active nitrogen-containing TiO₂ photocatalysts prepared by spray pyrolysis

Yellow-colored N-containing TiO₂ (NTO) powders with a porous surface were synthesized by spray pyrolysis. Their nitrogen contents depended on pyrolysis temperature and ranged from 300 to 5700 ppm. Ultraviolet-visible spectra indicated that the NTO powders could absorb not only ultraviolet light like pure TiO₂ powder, but also part of the visible light spectrum (λ < 550 nm). Acetaldehyde decomposition was used as a probe reaction to evaluate the photocatalysis of these sprayed powders. The photocatalytic activity of the sprayed NTO powder was superior to that of a pure TiO₂ sample under visible light irradiation.