Thin silica shell on Ag(3)PO(4) nanoparticles augments stability and photocatalytic reusability

Semiconductor photocatalysts are promising cost-effective materials for degrading hazardous organic contaminants in water. Ag(3)PO(4) is an efficient visible-light photocatalyst for the oxidation of water and dye degradation. The excited Ag(3)PO(4) photocatalyst uses a hole to oxidise water or organic contaminants except the electron, which reduces Ag(+) to Ag(0). In the present study, the inherited disadvantage was overcome by a thin silica shell overcoating on Ag(3)PO(4) nanoparticles. The silica-coated Ag(3)PO(4) nanoparticles retain the photocatalytic activity even after five cycles of photodegradation, while the bare Ag(3)PO(4) nanoparticles show a photocatalytic activity declined to half. The study demonstrates that the thin silica shell enhances the photostability, keeping the photocatalytic activity unaffected, even after several cycles of photodegradation of dyes. XPS analysis showed that the Ag(0) formation on the surface of bare Ag(3)PO(4) is greater than that on silica-coated Ag(3)PO(4), which declines the photocatalytic activity of Ag(3)PO(4) after five cycles of photodegradation. Electrochemical studies identified that the intermediates, such as OH˙ and O(2)(−), formed during water oxidation play a crucial role in the photodegradation of dyes. This study can provide insights into the design of core–shell semiconductor nanostructures for reusable photocatalytic applications.