Preparation, characterization and photocatalytic activity of N-containing ZnO powder

N-containing ZnO photocatalyst was prepared by decomposition of zinc nitrate at different heat treatment conditions. The photocatalyst was characterized by DRS, XRD, TG-DTA, XPS, and BET analysis. The results show that the optimum preparation condition for N-containing ZnO is at 350 °C for 3 h, and the sample shows higher photocatalytic activity. The photo-absorption wavelength range of the samples is shifted to long wavelength. Compared with pure ZnO, the samples show higher visible-light photocatalytic activity. However, under UV irradiation, the photocatalytic reduction activity of the N-containing ZnO is higher than that of pure ZnO, and the photocatalytic oxidation activity of the N-containing ZnO is much lower than that of pure ZnO. It is proposed that the change of photocatalytic activity of the sample should be attributed to the nitrogen introduction. The doped nitrogen atoms in a ZnO crystal lattice will probably cause the conductivity conversion of the sample from n-type to p-type.