The enrichment of silver ions in Ag3PO4 through the morphology changes and their photocatalytic activities

Abstract

The Ag₃PO₄ photocatalyst has been developed to degrade the organic pollutant due to its highly active responsive under visible light irradiation. The properties of Ag₃PO₄ may depend on design and preparation. Starting materials and co-precipitation conditions would significantly affect the properties of the product. The controlled defect of this photocatalyst may lead to improve catalytic activity. Here, the unique properties of phosphate deficiency in Ag₃PO₄ were created using the starting material of KH₂PO₄ and AgNO₃ under a mixed solvent of water and ethanol. AgNO₃ solution with the ethanol percentages of 0%, 25%, 50%, 75% and 90% was added to KH₂PO₄ aqueous solution.  The photocatalysts were characterized using XRD, DRS, SEM, and XPS. The changes in morphology can be observed from the tetrahedral to the sphere which has smaller particles.  The increased atomic ratio of Ag/P and Ag/O suggests that the silver ion enrichment in Ag₃PO₄ has been created. The activity of Ag₃PO₄ for Rhodamine B elimination increased by 4.3 times higher compared to that of the pristine Ag₃PO₄. The enhanced photocatalytic activity might be caused by the smaller particle size and higher silver ion content on the surface of Ag₃PO₄.