Enhanced visible light photocatalytic activity of octopod Ag₃PO₄ microcrystals with high index crystal faces

Novel octopod shaped Ag₃PO₄ microcrystals were successfully fabricated by a simple ion exchange method under the conditions of a hot water bath using [Ag(NH₃)₂]⁺ solution and Na₂HPO₄ solution as the precursors. Meanwhile, sphere and cube shaped Ag₃PO₄ microcrystals were also prepared followed by changing reaction materials as well as temperature. The surface morphology, microstructure and photocatalytic performance were investigated on the three different shaped crystals respectively. Compared to sphere and cube counterparts, the obtained octopod shaped Ag₃PO₄ crystals possess 8 symmetric feet with sharp tips and exhibit higher photocatalytic activity and better cycle stability. After further exploring its formation process, UV-vis diffusion reflectance properties as well as photocurrent transient response, it was found that the Ag₃PO₄ octopod had exposed high index crystal faces, and possessed a narrow band gap as well as high photoexcited transient charge separation efficiency. The results show that the improved photocatalytic activity of octopod shaped Ag₃PO₄ is mainly due to the synergistic action of the strong light absorption capacity and high carrier separation efficiency. These results highlight the tremendous practical application of octopod Ag₃PO₄ microcrystals in visible light photocatalysis.