Rapid Synthesis Method of Ag₃PO₄ as Reusable Photocatalytically Active Semiconductor

The widespread use of Ag₃PO₄ is not surprising when considering its higher photostability compared to other silver-based materials. The present work deals with the facile precipitation method of silver phosphate. The effects of four different phosphate sources (H₃PO₄, NaH₂PO₄, Na₂HPO₄, Na₃PO₄·12 H₂O) and two different initial concentrations (0.1 M and 0.2 M) were investigated. As the basicity of different phosphate sources influences the purity of Ag₃PO₄, different products were obtained. Using H₃PO₄ did not lead to the formation of Ag₃PO₄, while applying NaH₂PO₄ resulted in Ag₃PO₄ and a low amount of pyrophosphate. The morphological and structural properties of the obtained samples were studied by X-ray diffractometry, diffuse reflectance spectroscopy, scanning electron microscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity of the materials and the corresponding reaction kinetics were evaluated by the degradation of methyl orange (MO) under visible light. Their stability was investigated by reusability tests, photoluminescence measurements, and the recharacterization after degradation. The effect of as-deposited Ag nanoparticles was also highlighted on the photostability and the reusability of Ag₃PO₄. Although the deposited Ag nanoparticles suppressed the formation of holes and reduced the degradation of methyl orange, they did not reduce the performance of the photocatalyst.