Synthesis of nitrogen-containing ZnO powders by spray pyrolysis and their visible-light photocatalysis in gas-phase acetaldehyde decomposition

Colored N-containing ZnO powders with high surface area were synthesized by spray pyrolysis. The total nitrogen concentration was controlled from 600 to 1400 ppm by changing the pyrolysis temperature. The concentration of nitrogen doped into the sites of the ZnO crystal lattice by replacing oxygen atoms ranged from 400 to 900 ppm. Ultraviolet-visible spectra indicated that the N-containing ZnO powders could absorb not only ultraviolet light (λ<387 nm) like pure ZnO powder, but also part of the visible light (λ<650 nm). Acetaldehyde decomposition was used as a probe reaction to evaluate the photocatalysis of these N-containing ZnO powders. The photocatalytic performance of the sprayed N-containing ZnO powder was superior to that of a pure ZnO sample under visible light irradiation. However, nitrogen introduction did not remarkably improve the UV photocatalytic activity of ZnO.