Design of Ag₃PO₄ for highly enhanced photocatalyst using hydroxyapatite as a source of phosphate ion

The effect of hydroxyapatite on structure, particle size, and band gap energy of silver orthophosphate (Ag₃PO₄) have been investigated. The hydroxyapatite as a source of phosphate ion was prepared using the coprecipitation of CaCl₂ and KH₂PO₄. To produce the product of Ag₃PO₄, the as-synthesized hydroxyapatite was suspended in water and quickly added to a silver nitrate solution. The obtained photocatalysts were characterized using XRD, SEM, DRS, and XPS. The high crystallinity of single phase Ag₃PO₄ was easily produced using the hydroxyapatite. Photocatalytic activities of the product were evaluated using RhB decomposition under blue light irradiation. The hydroxyapatite as a source of phosphate ion dramatically decreases the particle size and increases the absorption in the visible region. This obtained photocatalyst significantly improves the photocatalytic activity. The mechanism of reaction works in the following order: holes > superoxide radical > hydroxyl radical.