Enhancement of photocatalytic activity of sprayed nitrogen-containing ZnO powders by coupling with metal oxides during the acetaldehyde decomposition

Abstract

Colored N-containing MO x –ZnO (M=W, V) composite powders with high surface area were synthesized by spray pyrolysis. The nitrogen content was controlled from 600 to 3000 ppm by changing the powder ingredients and the spray pyrolysis temperature. Ultraviolet–visible spectra indicated that the N-containing MO x –ZnO powders absorbed not only ultraviolet light like pure ZnO powder, but also some visible-light. Acetaldehyde decomposition was used as a probe reaction to evaluate the photocatalysis of these MO x –ZnO powders. The photocatalytic activity of the N-containing ZnO powder was pronouncedly enhanced by the WO 3 or V 2O 5 addition under both UV and visible-light irradiation. This enhancement was ascribed to the MO x acting as a sink for photogenerated electrons in the UV case, and to a synergistic effect of N-doping and MO x –ZnO coupling in the case of visible-light.