Enhancement of Photocatalytic Water Oxidation Activity on IrOx−ZnO/Zn2−xGeO4−x−3yN2y Catalyst with the Solid Solution Phase Junction

A three-component photocatalyst IrO x −ZnO/Zn 2− x GeO 4− x −3 y N 2 y was designed and investigated for photocatalytic O 2 production under visible light irradiation. It was found that loading of IrO x or ZnO alone could efficiently improve the photocatalytic activity. The even higher photocatalytic activity was achieved by coloading of IrO x and ZnO on Zn 2− x GeO 4− x −3 y N 2 y, which was about 5.6 times that of Zn 2− x GeO 4− x −3 y N 2 y alone. The photocatalysts simultaneously coloaded with IrO x and ZnO on Zn 2− x GeO 4− x −3 y N 2 y showed higher photocatalytic activities than those coloaded with IrO x and ZnO sequentially. The high resolution transmission electron microscopy (HRTEM) characterization showed that a solid solution phase junction (SSPJ) was possibly formed at the interface of ZnO and Zn 2− x GeO 4− x −3 y N 2 y nanaoparticles. This phase junction formed between ZnO and Zn 2− x GeO 4− x −3 y N 2 y may promote the charge separation and consequently result in the enhanced photocatalytic activity.